Mine Closure Handbook

ENVIRONMENTAL TECHNIQUES FOR THE EXTRACTIVE INDUSTRIES P. M. Heikkinen (ed.), P. Noras (ed.), and R. Salminen (ed.), GTK...

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ENVIRONMENTAL TECHNIQUES FOR THE EXTRACTIVE INDUSTRIES P. M. Heikkinen (ed.), P. Noras (ed.), and R. Salminen (ed.), GTK U.-M. Mroueh, P. Vahanne, M. M. Wahlström, T. Kaartinen, M. Juvankoski, E. Vestola, E. Mäkelä, VTT T. Leino, Outokumpu Oyj M. Kosonen, Maa ja Vesi Oy T. Hatakka, J. Jarva, T. Kauppila, J. Leveinen, P. Lintinen, P. Suomela, GTK H. Pöyry, Outokumpu Mining Oy P. Vallius, J. Nevalainen, Salvor Oy P. Tolla, Tieliikelaitos V. Komppa, VTT

MINE CLOSURE HANDBOOK

Environmental Techniques for the Extractive Industries

P. M. Heikkinen (ed.), P. Noras (ed.), and R. Salminen (ed.), GTK U.-M. Mroueh, P. Vahanne, M. M. Wahlström, T. Kaartinen, M. Juvankoski, E. Vestola, E. Mäkelä, VTT T. Leino, Outokumpu Oyj M. Kosonen, Maa ja Vesi Oy T. Hatakka, J. Jarva, T. Kauppila, J. Leveinen, P. Lintinen, P. Suomela, GTK H. Pöyry, Outokumpu Mining Oy P. Vallius, J. Nevalainen, Salvor Oy P. Tolla, Tieliikelaitos V. Komppa, VTT


Espoo 2008

Mine Closure Handbook Environmental Techniques for the Extractive Industries ISBN 978-952-217-042-2 ISBN 978.952-217-055-2 (PDF)

Cover photo: Listed pit head frame of the Keretti mine and tailings area landscaped into golf course in Outokumpu, Finland. (Photo: P. Heikkinen).

Vammalan Kirjapaino Oy 2008



FOREWORD This handbook has been prepared during the TEKESfunded project ‘Environmental Techniques for the Extractive Industries’ (in Finnish, ‘Kaivostoiminnan ympäristötekniikka’), which was undertaken as a joint research project between industry and various agencies during the years 2003-2005. The project was coordinated by Outokumpu Oyj with supporting industry partners being Tieliikelaitos (TLL, the Finnish Roads Enterprise) and Maa ja Vesi Oy (M&V Oy, Soil and Environment Ltd, which has since been incorporated into Pöyry Environment Oy). Public sector agencies participating in the project were Geologian tutkimuskeskus (GTK, Geological Survey of Finland) and Valtion teknillinen tutkimuskeskus (VTT, Technical Research Centre of Finland). Preparation of this handbook was one of the central objectives of the Environmental Techniques for the Extractive Industries project. Background research for the handbook included comprehensive reviews of relevant literature and analysis of various issues relating to the mine closure process, including Finnish and international legislation and best practice procedures, risk assessment, procedures for evaluating the long-term behaviour of tailings and waste rocks; hydrological and geochemical modelling; and post-closure monitoring strategies. The Hitura nickel mine at Nivala in western Finland was chosen as a case study for demonstrating

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planning and implementation of environmental management and closure programs. Investigations were carried out by four separate working groups, under the guidance of their respective group leaders; an outline of these research activities is documented in Appendix 15, while research reports are archived and available from the relevant participating organization. Responsibility for production of the handbook rested with a working group coordinated by Pentti Noras (Deputy Director/International Services, GTK) and comprising Päivi M. Heikkinen (Environmental geologist, GTK), Ulla-Maija Mroueh (Senior Research Scientist, VTT), Pekka Vallius (Production manager, TLL/Salvor Oy), Reijo Salminen (Research Professor, GTK), Erkki Ikäheimo (Vice President, M&V Oy), Eero Soininen (Resident Manager/Mine Reclamation, Outokumpu Oyj) and Veikko Komppa (Professor, VTT). Individual sections of the handbook were written by Päivi M. Heikkinen, Jussi Leveinen (Senior Research Scientist), Pentti Noras, Tarja Hatakka (Geologist), Jaana Jarva (Geologist), Tommi Kauppila (Senior Research Scientist), Petri Lintinen (Senior Research Scientist) and Pekka Suomela (Lawyer), GTK; Ulla-Maija Mroueh, Pasi Vahanne (Senior Research Scientist), Margareta Wahlström (Senior Research Scientist), Tommi Kaartinen (Research Scientist), Elina Vestola (Research Scientist), Markku Juvankoski (Re-

Mine Closure Handbook P. M. Heikkinen, P. Noras and R. Salminen (eds.)

search Scientist) and Esa Mäkelä (Team Leader), VTT; Tiina Leino (Manager of Environmental Legal Issues), Outokumpu Oyj; Heimo Pöyry (General Manager), Outokumpu Mining Oy; Mirja Kosonen (Vice President), Maa ja Vesi Oy; Jukka Nevalainen (Production Manager) and Pekka Vallius, Salvor Oy and Panu Tolla (Geotechnical Services Manager), Tieliikelaitos. Editorial responsibilities were shared by Päivi Heikkinen (GTK), Pentti Noras (GTK) and Reijo Salminen (GTK). The handbook was translated into English jointly by MSc Peter Sorjonen-Ward and a translation company The English Centre. The project was supervised by a steering committee which included representatives from each of the participating organizations, chaired by Veikko Komppa (VTT); other members were Matti Koponen (Senior Vice President/Corporate Environmental Affairs), who on retirement was succeeded by Eero Soininen, Outokumpu Oyj; Pekka Vallius, Salvor Oy; Erkki Ikäheimo, Maa ja Vesi Oy; Reijo Salminen, Pentti Noras and Päivi Heikkinen, GTK and also Esa Mäkelä and Ulla-Maija Mroueh, VTT. Comments and feedback on the content of the handbook were also invited from relevant permitting authorities, including the Ministry of Trade and Industry (KTM), the Safety Technology Authority of Finland (Tukes), and Environmental Permit Authorities, as well as from environmental


authorities (Ministry of the Environment, ‘YM’, and Finnish Environment Institute, ‘SYKE’), mining industry stakeholders (including members of the Association of Finnish Extractive Resources Industry, ‘Kaivannaisteollisuusyhdistys’) and other specialists in the field. A meeting with relevant authorities was also arranged during the drafting process, to solicit ideas and responses concerning handbook content and preparation strategy. The handbook was first introduced to interested stakeholders at a seminar on environmental management for the mining industry organized by the Lapland Regional Environment Centre (7.–8.4.2005), and subsequently at a training course convened by the Finnish Environment Institute (SYKE) on dam safety issues (27.9.2005) and at a meeting organized by the Association of Finnish Extractive Resources Industry (Kaivannaisteollisuusyhdistys) (19.10.2005). Without the initiative and enthusiastic encouragement provided by the late PhD Matti Koponen, in his capacity as Senior Vice President of Corporate Environmental Affairs for Outokumpu Oyj, neither the TEKES project, nor ultimately, this handbook would have proceeded beyond the planning stage.

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Figure 1. Hitura Ni-Cu mine, Nivala, Finland. Open pit is in the foreground, with waste rock and overburden stockpiles and concentrator plant behind. Tailings impoundment and settling ponds are visible in the background.

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ABBREVIATIONS AND ACRONYMS AAS ALD AMD AP ARD BAT BOD BREF COD DETR DME DTLR EC EIA EIPPC EM EMAS EPA EPER ERT EEA EU F FMEA GPS GTK HAZOP

Atomic absorption spectrophotometer Anoxic limestone drain Acid mine drainage Acid production potential Acid rock drainage Best available techniques Biological oxygen demand BAT reference document Chemical oxygen demand Department of the Environment, Transport and the Regions Department of Minerals and Energy, Republic of South-Africa London Department for Transport, Local Government and the Regions European Commission Environmental Impact Assessment European Integrated Pollution Prevention and Control Electromagnetic The Eco-Management and Audit Scheme U.S. Environmental protection agency European Pollutant Emission Register Electrical resistivity tomography European Economic Area The European Union Safety factor Failure Mode and Effects Analysis Global positioning system Geological Survey of Finland Hazard and Operability Study


ICP-AES/MS Inductively Coupled Plasma Atomic Emission Spectrometer / Mass Spectrometer ISO International Organization for Standardization KHO The Supreme Administrative Court KTM Ministry of Trade and Industry L/S-ratio Liquid-Solid ratio MCA Multi-Criteria Analysis MEND Mine Environmental Neutral Drainage (A Canadian research project) MMSD Mining, Minerals, and Sustainable Development -Project NDir Directive of European Commission NP Neutralization potential NNP Net neutralization potential (NP-AP) OLD Open limestone drain PAH Polyaromatic hydrocarbons PIMA Polluted soils PIRAMID Passive in-situ remediation of acidic mine / industrial drainage (EU-project, www.piramid.org) RAPS Reducing and alkalinity producing system SGY Finnish Geotechnical Association SYKE The Finnish Environment Institute TEKES Finnish Funding Agency for Technology and Innovation TEM Ministry of Employment and the Economy TUKES Safety Technology Authority of Finland UNEP United Nations Environmental Program VTT Technical Research Centre of Finland WHO World Health Organization YM Ministry of the Environment

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1. INTRODUCTION

1.1 OBJECTIVES AND SCOPE OF THIS HANDBOOK The purpose of this handbook is to provide mine operators, regulatory authorities and industry consultants with guidelines relating to planning and implementation of mine closure strategies. Closure as defined here covers a range of activities and procedures, relating to and following the point at which production finally ceases permanently, from decommissioning of plant and relinquishment of title, through to implementation and ongoing monitoring of site rehabilitation programs. In some circumstances, temporary closure may occur due to external factors, such as unfavourable commodity prices, or through change of ownership. In these situations it is expected that production will be resumed at some stage and there is generally no need to initiate formal, large-scale closure procedures. Therefore, mines placed under temporary care and maintenance, are beyond the scope of this handbook. There is no single law or decree that specifically deals with all obligations relating to the mine closure process. Rather, there are a number of acts and regulations, which control mining operations and closure. For some activities, legislation defines objectives and provides an operational framework, while in practice, decisions are typically made using a combination of best practice and previous experience. The handbook includes general guidelines and principles for mine closure, and presents suggestions for closure procedures and methodologies that are based on Finnish and EU legislation, with the aim of establishing and promoting a uniform best practice code for the entire mine closure process. Although the purpose of the handbook is to provide general guidelines, each case needs to be assessed on an individual basis, taking into consideration such diverse factors as mineralogy and chemical composition of the ore, mining method, nature of surrounding environment and land use priorities, the scale of mining operations and the type of enrichment and processing used. As a general principle however, the primary stated objective of successful mine closure is to ensure that the form mine site is restored to a condition where it no longer represents any kind of environmental, health or safety risk. To achieve this objective, it is also desirable that closure planning is seen as an integral part of the mining process from its inception.

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The handbook is structured such that the introductory section provides a background to the mining process, including the overall life-cycle perspective and environmental context of mining, together with a brief review of the diversity and significance of mining activities in Finland. Then an overview of general objectives and principles relating to concept of mine closure will follow with a more detailed discussion of legal and environmental issues. Nevertheless, the intention is not to provide an exhaustive guide to the entire legislative framework, but to provide the relevant regulations for mine closure. Chapters 4 and 5 describe procedures for planning closure strategies and various approaches to assessment of risk and environmental impact, together with illustrative examples of practical research methods available for assessment, monitoring and remediation. Chapter 6 progresses from assessment through to actual implementation of the closure process, describing technical solutions and risk management procedures. Finally, there is a description of necessary ongoing monitoring requirements that continue after mining has ceased, and some issues related to ensuring provision of sufficient financial resources for meeting closure obligations. Additional information and examples are presented in the Appendices, including a comprehensive summary of environmental regulations and responses required by the mine operator, as well as a general proposal for design of the closure plan. The handbook also contains a glossary of relevant terminology, based on the EC Reference Document for Best Available Techniques for Management of Tailings and Waste Rock in Mining Activities (EC 2004), and a supplementary explanatory guide to the application of relevant terms in their Finnish context by Himmi & Sutinen (2005). The handbook is intended primarily to provide closure guidelines to mine operators in Finland, either at existing mines, or for projects entering the production phase. The guidelines have been formulated in particular for metallic and industrial mineral deposits, but will also be relevant to the appropriate extent to commercial quarrying of dimension stone – primarily soapstone and marble (quarrying is regulated by Mining Act 503/1965) – and to restoration programs at previously Mine Closure Handbook P. M. Heikkinen, P. Noras and R. Salminen (eds.)

closed mine sites, as well as for a variety of mining activities outside Finland. However, the handbook has intentionally excluded closure and remediation strategies in relation to mining of radioactive materials or to quarrying related to production of natural stone or crushed rock aggregate, regulated by Land Extraction Act (555/1981). A guide to site rehabilitation following quarrying natural stone, in accordance with Land Ex-

traction Act, has previously been compiled and published (Alapassi et al. 2001). The handbook was originally published in Finnish in 2005. Thereafter, some changes in the environmental legislation, for example concerning the contaminated soils, have come into effect. During the translation process, the most relevant changes were updated in this English version of the handbook.

The handbook provides general guidelines for mine closure planning. Decisions on closure strategy should always be ultimately based on a case-specific assessment, taking into consideration the full diversity of characteristics and requirements at each mine site.

1.2 OPERATING ENVIRONMENT AND NATURE OF THE MINING INDUSTRY The following sections briefly outline the various phases of a mining operation, from exploration through to decommissioning and the potential environmental impacts of each of these activities. In addition, the nature of mining is considered in the context of sustainable development, followed by an overview and an assessment of the significance of the mining industry in Finland.

1.2.1 An overview of mining activities and the mining life-cycle Mining activity refers to the extraction and enrichment or refinement of metallic ores, coal and industrial mineral deposits. In Finland, the range of commodities exploited by the mining industry, fall under the operational jurisdiction of the Mining Act (503/1965). These commodities are grouped into four categories: 1) metallic ores, 2) industrial minerals, 3) gemstones, and 4) marble and soapstone (Table 1). It should thus be noted that marble and soapstone are the only natural stone commodities that are covered by the Mining Act. Quarrying of other dimension stones and crushed rock aggregate requires permitting and compliance under the distinct Land Extraction Act (555/1981). The mining life-cycle can be divided into three main stages, namely exploration, production and rehabilitation (Figure 2). The exploration phase commences with regional area selection to define the most prospective terrain, based to a large extent on previously available geological, geochemical and geophysical data, Environmental Techniques for the Extractive Industries

supplemented by reconnaissance investigations and surveys. Preliminary exploration at this stage requires normally an expression of interest alone (Mining Act 530/1965, Section 3). Decisions concerning more local targeting strategies are then made on the basis of these regional studies, at which stage it is customary to lodge a notice for a claim reservation at the register office of the appropriate local municipality, allowing more detailed investigations to be carried out over a period of twelve months. Under Section 7 of the Mining Act, this also confers a pre-emptive right in subsequently applying to the Ministry of Trade and Industry (KTM)1 for an exploration claim, usually over a more restricted, carefully defined area. It should be noted here that an exploration claim application must be submitted within a year of tendering a notice of reservation (Mining Act, Section 7). The intent of the exploration claim is to provide an opportunity for better delineation of resource potential, or to make a preliminary estimate of potential reserves (Mining Act, Sections 4 and 8). This process may require very detailed investigations, involving ground geological and geophysical surveys,

1

Since January 1, 2008 merger of the Ministry of Trade and Industry (KTM) and Ministry of Labour took place. The name of the new entity is Ministry of Employment and the Economy (TEM). The duties of the new ministry involve mining issues to the same extent as they were of the former KTM. The change took place after the final editing of the Handbook. Therefore, it should be considered as a correction to all of the following chapters and enclosures of the Handbook.

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sampling and trenching, drilling and trial mining and enrichment (Mining Act, Section 12). However, the exploration permit does not grant the right to exploit a mineral deposit identified during the exploration program. In some cases, the exploration process may continue for many years or even decades before either sufficient information is available, or circumstances are appropriate for commencement of planning a fullscale mining operation. Table 1. Groups of commodities that fall under the jurisdiction of Finnish mining law (Mining Act 530/1965, Section 2). Mineral commodity* 1) Li, Rb, Cs, Be, Mg, Sr, Ra, B, Al, Sc, Y, lanthanides, Ac, Th, U and other actinides, Ge, Sn, Pb, As, Sb, Bi, S, Se, Te, Cu, Ag, Au, Zn, Cd, Hg, Ga, In, Tl, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Co, Ni, Pt and other platinum group elements 2) Graphite, diamond, corundum, quartz, bauxite, olivine, kyanite, andalusite, sillimanite, garnet, wollastonite, asbestos, talc, pyrophyllite, muscovite, vermiculite, kaolin, feldspar, nepheline, leucite, scapolite, apatite, baryte, calcite, dolomite, magnesite, fluorite and cryolite 3) Gemstones 4) Marble and soapstone * Of these commodities, exploration, exploitation and beneficiation with respect to iron, alumina, quartz and feldspar is only permitted if they occur as deposits within bedrock.

Figure 2. a) Diamond drilling during exploration, b) open-cut quarrying of metamorphosed limestone at the Ihalainen mine, Lappeenranta, Finland, and c) underground operations at the Hitura Ni-mine, Nivala, Finland.

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If the intention is to commence mining operation, then a formal written application for a mining concession must be made to the Ministry of Trade and Industry. When the application has been processed and recorded in the national mining register, the applicant is issued with a permit granting the rights to commercially exploit the resources defined in the concession area (Mining Act, Sections 21 and 40). After the mining concession has been legally recognized, further studies are usually undertaken, involving more detailed drilling and reserve calculations, to refine and validate earlier inferences; the decision to proceed with mining then depends on the outcome of these estimates. Before any activity can commence, however, appropriate operating permits, including building and environmental permits, are required, and the operator must also submit a general mine plan to the Safety Technology Authority of Finland (‘TUKES’). Depending on the nature of the deposit, mining may be either as an open pit (Figure 2b), or else an underground operation (Figure 2c). Planning for an underground operation in particular needs to be very thorough and may require a number of years of preparation prior to production, for example if the main ore is at depth, and only accessible after construction a complex system of declines and tunnels and support facilities. This stage, as well as the main phase of production, produces variable amounts of waste rock, which needs to be dealt with somehow, usually by stockpiling someMine Closure Handbook P. M. Heikkinen, P. Noras and R. Salminen (eds.)

a)

b)

Figure 3. a) Waste rock pile at Siilinjärvi apatite mine, Finland, and b) tailings impoundment at Lahnaslampi talc mine, Sotkamo, Finland; tailings are spread as a slurry with a spigot distribution system.


has been mined, preparations for decommissioning and mine closure commence. The closure process not only deals with the cessation of technical operations, but also includes site rehabilitation, which involves both landscape restoration and prevention or mitigation of any potential environmental and safety risks. Closure may thus be viewed as an ongoing process, depending on local circumstances, with monitoring of rehabilitation potentially continuing for many years. Figure 4 presents a schematic summary of the mining life-cycle process, from exploration through to closure.

Mining life-cycle Duration

Activity phase

Permit stage

0 v. Area selection

0-2 v.

2-10 v. 5-15 v.

10-20 v. 10-25 v. 10-50 v.

Exploration

where on the mine site (Figure 3a). However, various options exist for using waste rock during mining, for example by backfilling of stopes, galleries and tunnels, and providing structural support. Waste rock can also be used above ground, as required for earthworks at the mine site. Ore and any waste rock that cannot be mechanically separated are transported to the crushing mill, or in some instances to crushing facilities installed underground. The crushed ore can then be processed by concentration plant on site, or transported elsewhere for further processing and enrichment, although not all mineral commodities require further treatment or enrichment on site. At the concentrator, ore is generally crushed further to a sufficiently fine grain size to allow separation of desired commodities either by physical or chemical means, for example by gravity, magnetic or electrostatic methods, or by leaching or flotation. The final concentrate is transferred by conveyor belt to storage bins, before transport for further processing. Metallic concentrate for example, will be taken to a smelter, where desirable metals will be separated from unwanted material. Tailings (Figure 3b) generated during enrichment are transported, usually as a slurry to a tailings impoundment, or if in solid form, may be returned to the mine as backfill material, or used in earthworks, either on the mine site or elsewhere. The duration of mining operations depends on the size and grade of the deposits and methods used, as well as prevailing commodity market prices. Although mining may occur over years or several decades, commodity price fluctuations might result in temporary breaks in production, or even lengthy periods of closure. However, when all economically recoverable ore

Regional study Target selection

Reservation

Prospect delineation

Exploration claim

Resource delineation, feasibility study Mining concession/ Mining right

Mine construction Production

Relevant permits for regulating operations

Shutdown and decommissioning

Rehabilitation and monitoring

Figure 4. Mining process life-cycle; time scale at left is indicative of duration of various phases of activity.

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1.2.2 Environmental impacts of mining activity Mining operations inevitably cause changes in the surrounding environment, the extent of which depends upon the nature of the ore, mining and treatment methods and the size, geometry and location of the deposit. The most significant effect on the environment typically relates to the establishment and mining production phase; exploration and resource delineation generally have little or no impact, although blasting during trial mining may produce noise and dust and possibly influence the local surface water and groundwater levels or water quality. Implementation of a rehabilitation program after mining has ceased is intended to ensure safety and to minimize potential negative environmental impacts of the closed mine. Without such precautionary measures, it is possible that environmental effects could persist for tens of years after mine closure. In Finland, mineral deposits can be grouped into four categories with respect to potential environmental impact, namely sulphide- and oxide metallic ores, industrial minerals and natural stones. The greatest potential impact is usually associated with the mining and processing of sulphide ores, for at all stages, from quarrying through crushing and stockpiling, sulphide grains exposed to the atmosphere and rainwater will tend to oxidize and weather (Figure 5). Oxidation of sulphides may promote the formation of acidic mine waters, which have the capacity to further leach metals and contaminate surface and groundwaters or soils, potentially resulting in restrictions in their use for domestic or recreational purposes. Deterioration of water quality and contamination of soil also constitute potential health risks to animals and humans. In contrast, mine-influenced waters associated with waste rock areas and tailings at mines in carbonate rocks tend to have relatively low metal abundances and circumneutral pH values, and consequently have only a minor effect on surrounding waters. The principal environmental effects in relation to mining of oxide ores and industrial minerals are in the form of dust derived from blasting in the mines and from tailings and waste rock facilities. Noise impact is the most prominent cause for concern during quarrying for natural stones (Aatos 2003). Both underground and open pit mining and associated activities can significantly modify the landscape at the site and hence have a major impact on vegetation and local ecosystems, and also influence land use options and human activities, from recreational or aesthetic perspectives. One of the most significant effects on the landscape is the removal of extensive overburden related to commencement of mining in an open pit. Underground mining operations also require removal

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Figure 5. Sulphide minerals in tailings oxidize when exposed to weathering, leading to precipitation of iron (oxy)hydroxides and imparting rusty brown colour (Aijala tailings area, Kisko, Finland).

of material during the initial construction of declines, tunnels and shafts. Although some of this waste rock can be replaced as backfill during mining or utilized, in the same way as overburden, in various earthworks, a quantity of waste rock is stockpiled in proximity to the mine. In addition to waste rock piles, the mine environment is variably affected by the construction of mine infrastructure, including various buildings, crushing mill, roads and water pipelines and electric cables. If a concentrating plant is built at the site, then a substantial area will need to be allocated for constructing a tailings impoundment, as well as for the plant itself, and storage facilities for the concentrate. Further modifications to landscape can occur if it is necessary to divert surface waters in proximity to the mine. The overall effect on the landscape will depend ultimately on the size of the mining operations and to some extent on the geometric configuration of the deposit. For example, a compact, contiguous ore body will obviously leave a Mine Closure Handbook P. M. Heikkinen, P. Noras and R. Salminen (eds.)

smaller disturbance than a more dispersed, low-grade deposit consisting of several or more separate lodes or structurally disrupted ore bodies. Quarrying, crushing and transport during mine production are all potential sources of excess noise, vibration and dust. Tailings and stockpiled concentrate may also cause dust problems (Figure 6). Dust may settle in surrounding surface waters, causing silt accumulation or chemical changes, not only to surface waters but also through subsequent infiltration into groundwater and soil, eventually representing a potential human health risk. Water and soil quality may also be adversely affected through stockpiling of waste rock and tailings at the mine, the handling and storage of chemicals and hazardous waste (for example used oil or processing chemicals), contamination by routine servicing and maintenance of machinery and equipment at workshops on the mine site, or through accidents and the residue from explosives used at the mine. The risk of groundwater contamination is likely to be greatest in situations where sulphide tailings and waste rock dumps are located over a highly permeable substrate and particularly if topographic relief results in a significant hydraulic head (see above). Open pit and underground operations both require pumping to keep the mine free of water, which tends to lower the ambient water table and may, therefore, have an impact on water supply to any nearby households or communities that are reliant on groundwater. Water pumped out of the mine is commonly either used during the ore enrichment process or is discharged into

the surrounding watershed, after removal of suspended matter in settling ponds. The original composition of these waters may be variably modified through mixing with water used for cooling or flushing during drilling, or which has percolated through backfill, or has been affected by other mining processes. In addition to contamination derived from interaction with ore and rock, these waters may contain chemical residues, including nitrogen compounds, from explosives and lubricants or processing and enrichment chemicals. Release of such waters into the surrounding watershed may reduce water quality downstream from the mine and have a negative impact on aquatic ecosystems. To prevent such occurrences, it is common practice to use a closed-cycle process to direct water from the settling ponds back into the processing circuit. Final discharge from the settling ponds is usually timed to coincide with heavy rainfall, when the capacity of the ponds may otherwise be exceeded, and increased flow rates during discharge will allow more effective dilution of any contaminant loading in the surrounding environment. If accumulation of supernatant water in the tailings impoundment is sufficient, then this water may also be pumped via settling ponds to be used in the closed-cycle enrichment process. The tables in Appendix 1 are compilations of different types of mineral deposits and respective potential environmental consequences of their mining and processing activities. In addition, Section 4.1 deals with environmental aspects of mining operations in more detail, with respect to risk assessment procedures.

Figure 6. Generation of dust from tailings areas can be minimized by watering (as in picture) or spreading a lime slurry (Zinkgruvan Zn-Pb mine, Sweden).


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1.2.3 Mining and sustainable development Mineral commodities and products are required in almost all industrial and manufacturing processes, which are in turn essential to provision of services to society (Figure 7). Materials derived from mining are also required at some stage in the utilization of many natural resources that are classified as renewable or energy-neutral. However, if oil and natural gas are excluded, then the exploitation and beneficiation of mineral resources represents less than 1% of the total volume of natural resources utilized annually (Raw Materials Group 2005). A flow chart depicting mineral resources and products within a global economic and environmental context is shown in Figure 7. Mineral resources cannot be classified as renewable at the time of extraction from host rocks, since this process, as well as downstream applications of mineral resources, contributes to resource depletion. However, if the efficient utilization of mineral resources is evaluated more broadly, and over a longer time frame, a somewhat different perspective emerges, for reasons such as the following: • Material mined from mineral deposits is by nature permanent, so that appropriately stockpiled tailings and waste rocks are in principle accessible to further exploitation, potential over hundreds of years. • Metallic elements occur in a wide range of minerals, not just those that are currently exploited, and therefore future beneficiation technologies may allow access to mineral deposits of different type or lower grade. • The global abundance of a number of important metallic elements (notably Fe and metals used in Fe-alloys, Al and Mg) remains far in excess of society requirements. • Rapid technological developments in exploration, processing and metallurgy mean that the mining industry is relatively more productive and energy efficient. • Almost limitless opportunities exist for substitution of many metals by other material, for example machine components requiring high strength and temperature resilience can be manufactured from ceramics or polymers. • Developments in engineering and material science allow increasing use of widely available mineral products in composite materials, more efficient use through miniaturization in the electronics industries, novel biotechnological applications and protecting from corrosion. • There appears to be an upper limit for production of many mineral commodities, such that their market

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price exerts an influence on demand, making efficient recycling of materials and components a more economically viable option. • General strategies to consume less, and consume more efficiently and responsibly are increasingly encouraged.

On the basis of such principles and in a view of the evident abundance of resources, the long-term sustainability of the minerals industry seems assured (Ericsson & Noras 2005). The goal of sustainable development is to reconcile current requirements for socio-economic development with management of a stable global environment and thus ensure a balanced social and environmental legacy for future generations. While a robust and sustainable ecosystem can survive short-term and local environmental pressures during resource exploitation, the long-term goal must be minimal environmental impact and restoration of any imbalances, wherever possible. During mining operations for example, it is very difficult to avoid having some impact on the quality of the local environment. The very nature of mining also makes virtually impossible to perfectly restore the mine site to its previous state, but with careful landscaping and removal or stabilization of potential physical and chemical hazards, it is possible to establish a diverse and functional ecosystem and plan options for post-closure land use. In terms of sustainability from a social perspective, mining operations can clearly be beneficial over the long-term in supporting skills and services, at least in proximity to the mine and potentially over a wider area as well. However, ensuring the future stability and well-being of a community (largely dependent upon mining) after operations cease, requires careful planning and evaluation of options well in advance of mine closure. With these caveats in mind, the overall effect of mining over the long-term may be argued as bringing a net benefit in terms of community stability and prosperity and thus satisfies many sustainable development criteria (Table 2). However, attainment of a sustainable solution still requires effective response to and management of these issues. The downstream impact of the minerals industry on a global scale, both through direct consumption of manufactured goods and their further utilization within the services sector, is already considerable and continues to accelerate. Production and consumption of manufactured goods is a fundamental prerequisite for current social, cultural and domestic prosperity, yet there is an increasing awareness of the environmental impact and long-term sustainability of such growth. There are accordingly strong ethical as well as economic incentives for the minerals industry to demonMine Closure Handbook P. M. Heikkinen, P. Noras and R. Salminen (eds.)

Environment (”ecosystem”)

Ore

Impacts of product use Mining operations

Processing

Refined product/ Trading

Product use

Waste management

Trading partners/Trading regime

Figure 7. System of material flows and stocks. Stocks of unrefined and processed minerals industry resources (yellow box) and material flows (black arrows). Dark blue and red arrows track utilization of mineral resources, emissions and trade. Return-flow feedback loops (“new” and “old” scraps) are indicated by arrows directed from right to left. The impact of certain manufactured products and activities, notably vehicles and transport, though significant in many ways, is not included within the mineral resources flow analysis. Diagram is modified after Muller & Graedel (2003).

Table 2. Minerals industry and related derivative products, and their respective sustainability. Phase in mineral commodities utilization

Social prosperity and well-being

Ecosystem functionality

Sustainability

Comments

Mining operations

•

•

• •

•

Improving (assuming responsible govern)

Stable/Slight deterioration

Sustainable Almost sustainable

•

Local, short-term sustainability issues Risk management procedures ready for implementation

Product manufacture

•

Improving

•

Stable/Slight deterioration

• •

Sustainable Almost sustainable

•

Essential for economic growth: energy flows and recycling are important criteria

Consumption of goods and services

• •

Increasing Decreasing (negative feedback loop with environmental quality)

• •

Stable Significant deterioration

•

Sustainable (exploitation balanced) Unsustainable (over consumption)

•

Essential to long-term social and cultural stability Sustainable management is a global challenge

strate the implementation of socially accountable and ecologically sustainable practices, particularly given that 1) required technological solutions are to a large extent, already available, 2) a number of international regulations and treaties and codes of conduct are in place or under negotiation, and 3) additional expenditure for implementing reforms are generally modest. However, irrespective of the success and impact of such reforms in the resources sector, it is clear that as long as society promotes increased material consumption and global population continues to increase, economic growth is not sustainable from a long-term environmental perspective. The transition to an equitable global society less demanding of finite resources remains the greatest challenge facing humanity.


•

•

1.2.4 The mining industry in Finland – past and present Finland has a long tradition of mining, with the earliest documented operations being the Ojamo iron mine at Lohja, apparently dating back to before 1530. Since then, more than a thousand metallic ore, industrial mineral, and carbonate rock deposits have been exploited. While Finland was administered as part of the Kingdom of Sweden, all mineral resources were property of the Swedish Crown, which also had exclusive mining rights, until 1723, when the first general mining legislation was formulated (Puustinen 2003). These early laws dealt with claim procedures and mining leases and procedures, and defined respective rights of landowners and the discoverer of an ore deposit. The Mining Act introduced in 1965 currently regulates exploration and mining activities in Finland. Since late Swedish rule,

17

mining affairs were administered by the “Collegium of Mines”, then under Russian administration by an office of the Finance Ministry (1816), then by a separate Board of Mines (1858), after which mining activities fell under the authority of a more general Board of Industries (1885). Finland became an independent sovereign state in 1917 and, from 1919, the mining industry was regulated and administered firstly by the Board of Trade and Industry, and subsequently by its successor, the current Ministry of Trade and Industry. Since 1994, when Finland joined the European Economic Area (EEA), it has been possible for foreign exploration and mining companies to operate in Finland. In the period following the Second World War, the number of metallic mining operations in Finland was greatest in 1974, with a total of 22 separate deposits being mined, while the largest combined annual production, of 10.3 Mt was in 1979. Since 1980, the number of mines in operation and total production have both decreased rapidly. In contrast, there has been a significant increase in industrial mineral production over the last two decades, although there has been a general decrease in the number of deposits exploited. Carbonate rocks are an exception in that the number of mines and the production volumes have both continued to increase in recent decades, with 18 separated deposits being worked throughout the 1990’s (Puustinen 1990). The maximum number of industrial mineral deposits being mined simultaneously was 26 in 1980. There is currently no production of iron ore in Finland, the last operations having closed in 1990. Closure of operations for the more significant sulphide and oxide mines in Finland over time is as follows: • 1950–1960: Orijärvi (Kisko), Makola (Nivala), Jussarö (Tammisaari), • 1960–1970: Haveri (Viljakkala), Aijala (Kisko), Ylöjärvi, Kärväsvaara (Kemijärvi), • 1970–1980: Korsnäs, Metsämonttu (Kisko), Kylmäkoski, Raajärvi (Kemijärvi), • 1980–1990: Luikonlahti (Kaavi), Hällinmäki (Virtasalmi), Vuonos (Outokumpu), Hammaslahti (Pyhäselkä), Outokumpu, Kotalahti (Leppävirta), Otanmäki (Vuolijoki), Mustavaara (Taival koski), Rautuvaara (Kolari), • 1990–2000: Ruostesuo (Kiuruvesi), Vihanti, Saattopora (Kittilä), Pahtavuoma (Kittilä), Pampalo (Ilomantsi), Telkkälä (Taipalsaari), Hälvälä (Kerimäki), Laukunkangas (Enonkoski), Stormi (Vammala), Hannukainen (Kolari), and • 2000–2004: Mullikkoräme (Pyhäsalmi).

Two deposits in Finland are ranked as world-class in terms of tonnage and production, namely the carbon-

18

atite-hosted apatite deposit at Siilinjärvi and the chromite ores at Kemi. Other significant deposits in terms of European production have been the Outokumpu and Vuonos Cu-Co-Ni-Zn ores, the Pyhäsalmi and Vihanti Zn-Cu ores, the Lahnaslampi talc deposits, and the Ihalainen carbonate-wollastonite deposit. Cumulative total production from metallic mines in Finland between 1530–2001 is around 480 Mt, of which processed and refined ore accounts for 270 Mt. Cumulative production figures for industrial minerals are 267 Mt of ore mined with about 186 Mt of concentrate, while for carbonate rocks, respective values are in excess of 277 Mt mined, with nearly 240 Mt of processed ore (Puustinen 2003). In terms of total production, the most significant metallic ore deposits have been Pyhäsalmi (36 Mt), Outokumpu (32 Mt), Vihanti (28 Mt), Kemi (27 Mt), Otanmäki (25 Mt), Hitura (13 Mt), and Mustavaara (13 Mt); the most important commodities in terms of concentrate have been sulphur, iron, chromium, copper, zinc, ilmenite and nickel. Using the same criteria, the Siilinjärvi apatite mine has been by far the largest producer of industrial minerals, with over 144 Mt of ore processed. Amongst carbonate mines, largest producers have been Parainen (79 Mt), Ihalainen (>45 Mt), and Tytyri (>34 Mt). The above production figures are based on available data for the years 1950–2001 (Puustinen 2003). As of 2006, there were six metallic ore mines operating in Finland, 17 carbonate mines and 16 other industrial mineral operations, with a combined production of 20 Mt (Figure 8 and Table 3). The Kemi chromite mine and Siilinjärvi apatite mine together have accounted for a significant amount of total production particularly since 1980’s. Calculated earnings from the total amount of metallic ores mined in Finland, in present day terms, is in excess of 17 billion euro, of which copper has made the most valuable contribution (5,100 M€), followed by chromium (4,000 M€), zinc (3,800 M€), nickel (2,500 M€), iron (1,500 M€), and gold (300 M€). The cumulative equivalent calculated value of industrial mineral production is nearly 15 billion euro, of which the most significant commodities have been carbonate minerals (8,500 M€), talc (4,100 M€), and apatite (800 M€) (Puustinen 2003). These figures, nevertheless, represent only a fraction of the total contribution of the minerals industry to the economy, both domestically and outside Finland, if value-added activities from metals refining through manufacturing to provision of services are considered. The mining industry currently represents around 2% of Finnish GNP and directly employs about 9,600 people representing 1.8% of the total workforce; of these, only 662 people are involved in the operation of Mine Closure Handbook P. M. Heikkinen, P. Noras and R. Salminen (eds.)

metallic mines. However, an inherent and traditional characteristic of the minerals industry is the significant multiplier effect that the sector generates in terms of employment in the wider community, during valueadded processing, manufacturing and services. Given

this perspective, the minerals, mining and metals sector in Finland has a direct and indirect impact on employment of 211,000 people in Finland, or 39% of the workforce, and accounts for nearly 20% of manufacturing exports (Raw Materials Group 2002).

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3 10 years) • Requires only small area to operate effectively • Cost-effective compared to traditional neutralization techniques

• Moderately acidic mine waters, with dissolved O2 < 1mgL-1; Fe3+ < 2 mgL-1; Al3+ < 2 mgL-1; SO42- < 2000 mgL-1;

• Anoxic mine water channelled through buried and sealed cells of limestone • Carbonate dissolution increases pH of water and enhances buffering capacity

• Effective increase in water pH • Straightforward implementation

• Efficient at increasing water pH

Advantages

Anoxic limestone drainage (ALD)

• Acidic mine waters with relatively low metal concentrations

• All acidic mine waters

• Addition of alkaline material causes increase in pH • Metallic cations precipitate as (oxy)hydroxides and carbonates

Neutralization

Open lime• Limestone added to mine water outflow drainage stone channel systems (OLC) • pH of water increases, causing metal precipitation as (oxy)hydroxides and carbonates

Appropriate applications

Treatment mechanism

Method

Table 25. Examples of water treatment methods for different types of mine drainage. References

Mustikkamäki 2000

MEND 1996

MEND 1996; Gazea et al. 1996; PIRAMID Consortium 2003

MEND 1996; Gazea et al. 1996; PIRAMID Consortium 2003

PIRAMID Consortium 2003

• Risk of sealing and clogging reduces flow and Waybrant et al. 1998; renders process ineffective Mustikkamäki 2000 • Effectiveness sensitive to water temperature and compositional fluctuations • Suitable for relatively small flow rates

• Mineshaft needs to be sufficiently deep • Effectiveness sensitive to temperature and compositional fluctuations

• Expensive monitoring and maintenance • Suited to relatively small volumes of water

• Usually requires supplementary aerobic treatment • Effectiveness sensitive to temperature and compositional fluctuations

• Oxidation reactions tend to decrease water pH • Effectiveness sensitive to temperature and compositional fluctuations • Potential formation of undesirable flow channels

• System must be located at least 2.5 m below level at which mine waters are produced • Requires additional anaerobic or aerobic treatment for removal of metallic pollutants

• Susceptible to blockage of drainage channels MEND 1996; • Stringent requirements on composition of inflow PIRAMID Consortium water 2003 • Requires additional anaerobic or aerobic treatment for removal of metallic pollutants

• Requires regular replenishment of limestone Ziemkiewicz et al. 1997 • Tendency for reactivity to decline due to precipitation on limestone surfaces • Loss of limestone at high flow rates

• Need to physically remove and dispose of metal- Ledin & Pedersen 1996; lic precipitates MEND 1994 • High cost of chemicals and monitoring

Disadvantages

Figure 44. Potential seepage of water through tailings dams is contained by an effective system of trenches, which also channels water for further treatment as necessary (Zinkgruvan Zn-Pb mine, Sweden).

6.2.2 Procedures for covering tailings and waste rocks It is difficult to provide generic guidelines for covering procedures of waste rock and tailings management facilities. Overall, objectives and requirements need to be determined case-specifically, based on assessment of a range of criteria, including the nature of the tailings and waste rock materials and the cover material, hydrological and soil parameters and attributes at the rehabilitation site, and consideration of future land use requirements, as well as any technical difficulties that might arise, related to location, and availability of suitable covering material. Depending on the above site-specific characteristics, objectives of the covering program may be to: • prevent wind ablation of tailings or waste dumps and hence airborne transport of pollutants into the surrounding environment • ensure that the site remains inert over the long term • prevent or minimize the formation of acid mine drainage, by excluding transport of oxygen into the tailings or waste rocks • prevent leaching of metallic and other pollutants from the tailings and waste rocks by preventing the water infiltration into the materials • promote the establishment of a viable ecosystem in harmony with the surrounding environment


The nature of tailings, waste rocks and mine host rocks varies considerably, depending on whether the mine has been exploiting industrial minerals, sulphide ores or various other metals. Conditions and requirements for covering also vary further within these groups. Therefore, it is important to characterize the properties of the material to be covered in order to assess both the potential environmental impacts and risks related to the material, prior to deciding implementation strategy. It is also important to appreciate that extraction and transport of cover material to the site of rehabilitation may in itself have a significant impact on the surrounding environment and should therefore be incorporated into the decision-making process. In many instances, a reasonable solution, both financially and in terms of minimal environmental impact, is the temporary storage of topsoil and other material in close proximity to the mine in a manner that promotes their utilization. A flow chart depicting the process of design and implementation of a covering program is shown in Figure 45. When prescribing specific remediation programs, compliance with closure legislation (cf. Chapter 3) should be given first priority. Application of best practice technologies and solutions will presumably receive even more attention in the future. For example, the recently published EC mining industry guidelines on management of tailings and waste rocks (EC 2004) place particular emphasis on analysis of the whole

103

mining process, from planning to decommissioning and rehabilitation. While BAT reference documents are important, other sources of information contained in research and technical reports should also be used in deciding whether a given strategy is appropriate. There are essentially two options for isolating tailings and waste rock – burial beneath a layer of overburden, or covering with water, although the possibility of leaving tailings exposed may also be considered.

Options for leaving tailings uncovered The simplest procedure is to landscape the closed mine environment in whole while leaving tailings and waste rock areas uncovered. This may be acceptable if it can be shown that the tailings and waste rock management facilities are stable and pose no health risk or safety hazard to humans or wildlife through groundwater contamination or dust ablation. It is nevertheless necessary to take measures against the possibility of erosion over the long-term, by establishing vegetation, or controlling the flow of water through the area.

Dry cover layers Covering tailings or waste rock with a dry layer of overburden is an effective way of mitigating generation of dust, water infiltration and oxygen diffusion. At the same time, this approach generally provides enhanced conditions for plant growth, reduces the risk of erosion and can be integrated with landscape restoration. Prior to covering it is customary to dewater the tailings, and to allow consolidation of tailings. Some

form of temporary covering measure may be required at this stage, to prevent dust ablation. It is also necessary to deal with potential erosion and ponding of surface waters in the management facilities, by designing slopes with an appropriate angle of repose and using furrowing to and channels to arrest and divert water runoff (EC 2004). The thickness, structure and material properties of the cover layer will be determined by the nature of the tailings and other site characteristics, including the local water table, and the availability of and access to source material, all of which need to be considered thoroughly. If the material to be covered is reactive or susceptible to acid production, and the intention is to isolate the tailings from oxygen diffusion and water infiltration, the following features should also be examined carefully (Naturvårdsverket 2002): • The potential for interaction between the atmosphere and tailings or waste rock, for example via plant root systems or disruption of surface integrity by subsidence or some other mechanism • The possibility that seasonal temperature and rainfall fluctuations induce frost heave or desiccation cracking and thereby affect the effectiveness of the covering layer • Measures to mitigate the effect of erosion should also take into account extreme and unlikely events, such as flooding, or freezing and blockage of drainage networks

The risk of excessive acid production can be addressed by moderating the pH of the material to be

Adequate characterization of material properties of the covered tailings/waste rocks, during both initial planning phase and during ongoing implementation

Evaluation of potential use of tailings and waste rocks or any additional material extracted during the mining activities in the remediation

Storage of the materials at the mine site with respect to their characterization and potential usage so as to remain accessible for subsequent use

Investigation of processing opportunities (quarrying and concentration, mineral processing and metallurgical options, classification and refinement of tailings) which may enhance utilization of the disposable materials and further minimize environmental loading and risk

Design and construction of transient storage and final disposal areas, including assessment of potential environmental impacts and risks, mitigation strategies and recommended options for covering tailings and waste rock. Design of exit and monitoring plans

Regular review and revision of plans during mining operations and in response to changes

Storage of cover materials during mining operations, optimizing the covering process with attempt to minimize transport costs and need for storage

Final design of covering structure, including revised assessment of environmental impacts and risks

Figure 45. Designing the covering of the tailings and waste rock areas.

104


covered by addition of lime, crushed limestone or fly ash, prior to covering. The most straightforward method is to spread the cover material without any attempt at compaction or consolidation. This is appropriate in situations where there is no need to prevent the water infiltration into the covered material. If the covering material is inherently relatively impermeable, then it is possible to make an effectively impervious barrier by spreading and compacting two or more layers. Oxygen diffusion can be dealt with by designing the system such that the water table lies within the cover layer, but in this case it is necessary to ensure that there is no possibility of accidental release of acidic waters or solid waste material. A more effective approach to prevention of oxygen and water infiltration is by spreading two separate layers, a sealing layer (for example compacted impervious clay) and the surface layer. The upper layer thus protects the lower layer against the effects of erosion and structural degradation due to seasonal dehydration or freezing, as well as minimizing direct interaction with humans and other animals, plants and microbial activity. Moreover, this layered structure both disrupts upwards capillary flow and favours retention of any metal complexes transported by pore waters. The EC’s BAT reference document (EC 2004) also describes a further option in which the compacted layer is overlain by another layer intended to prevent the water infiltration and to promote drying of the substrate. However, excessive drying and potential desiccation of the surface layer may lead to oxygen infiltration to deeper levels. Moreover, in the long-term, the geotextile between the layers may deteriorate, leading to mixing of the layers and reduction of the effectiveness of the desiccation layer. In oxygen consuming cover layer a water-saturated, relatively impermeable structure also acts as an effective barrier to oxygen diffusion, since breakdown of organic matter in the surficial layer consumes oxygen. However, if organic matter promotes biologic reduction of iron, there is an increased risk of metal leaching. Conditions might also be favourable for bacterial sulphate reduction, although so far, neither of these processes has been documented during site monitoring. Dry cover methods have been widely used in mine site rehabilitation in the Nordic countries, for example at Enonkoski and Keretti (Outokumpu) in Finland and at Viscaria in Sweden. Further examples of this approach are listed in Appendix 13.

The use of water covers The use of water cover is appropriate in situations where the aim is to prevent oxygen infiltration into tailEnvironmental Techniques for the Extractive Industries

ings that are susceptible to acid production, the main reason being that oxygen diffusion rates are four orders of magnitude lower in water than in air (Robertson et al. 1997). However, covering by a layer of water requires that the following conditions are met: • Water must be available, even if the area is subject to seasonal dryness, in sufficient amounts to ensure that both the water table and water chemistry remain stable • Dams and impoundments are structurally stable over the long-term • Outflow channels are stable and with a capacity designed for coping with isolated extreme flood events, and also other eventualities, such as ice dams and log jams • Water depth above the tailings is deep enough such that wave action does not cause erosion or hydraulic separation and concentration of tailings.

The impoundment will function best if it is integrated with the surrounding watershed and is fed by inflow from a natural stream. This accelerates the restoration of a natural ecosystem by supplying organic matter, nutrients, and aquatic biota. Moreover, influx and deposition of sediment enhances the existing barrier to oxygen diffusion within the underlying tailings. The greatest uncertainties with respect to this approach lie in ensuring the long-term stability of the impoundment dams and that an adequate supply of water is maintained over the longer term, even after monitoring of the site has ceased. Appendix 13 documents examples of water-covered tailings schemes in Sweden.

6.2.3 Revegetation programs in landscape restoration Revegetation programs not only provide aesthetic enhancement of former mining sites, but also mitigate any adverse effects associated with tailings and waste rock areas and closed open pits and quarries, whether due to drainage issues or slope instability. Vegetation cover also effectively isolates potentially hazardous materials from contact with humans, animals and surface waters and prevents potential dust hazards, by a combination of binding soil and overburden and disrupting the effect of wind at ground level. Careful regeneration of vegetation also provides the opportunity for reversion to a balanced and viable ecosystem approaching that prior to the commencement of mining, which in turn enhances the value of the site, both aesthetically and in terms of alternative land use activities. Plants also have the capacity to bind toxic compounds in root systems and foliage, thereby reducing their bioavail-

105

ability and uptake into the surrounding environment (EPA 2000). Vegetation cover also inhibits the formation of acidic complexes, at least those of biological origin, through uptake of oxygen and moisture by root systems, which thereby reduces activity of bacteria whose metabolism generates acidic compounds (Ledin & Pedersen 1996). This effect will be further enhanced in the presence of heterotrophic bacteria and fungi, which also utilize oxygen and increase carbon dioxide levels in soils. The choice of appropriate plant species for regeneration requires consideration of soil attributes and climatic factors, as well as evaluation of future options for land use (see Table 26). Tailings and waste rock are generally poor in nutrients and organic matter and lack normal soil microbe populations, while tending to be acidic, and with elevated concentrations of potentially toxic elements. Waste rock heaps are also characterized by coarser rock fragments than in most soil substrates, and slopes may be steep. Therefore, ideal species for revegetation are opportunistic varieties, which germinate efficiently and grow rapidly, forming an effective ground cover and which are also capable of establishing themselves on a nutrient-poor, and porous, or rocky substrate. Ideally, such plants would also be tolerant to extremes of heat, frost and wind, and promote formation of humus, as well as being efficient in nitrogen fixation and transpiration. However, survival of an individual species is not as important as promoting the progressive establishment of a naturally viable vegetation regime. While natural regeneration would be ideal, in practice it is commonly necessary to undertake a systematic planting program, preferably with endemic Table 26. Recommendation of planting strategies according to intended land use (Karjalainen 2003). Type of land use

Revegetation strategy

Plantation forestry

•

Recommended, if intention is economically viable forest production

•

Fast growing plants with high yield

•

Plants resistant to physical impact, such as turf for sportsgrounds and playing fields

•

Slow-growing ground cover species

•

Requires careful risk assessment and monitoring during and after rehabilitation

•

Plants susceptible to uptake of toxic compounds

Natural landscape with no specific commercial or conservation objectives

•

Facilitate rapid colonization of vegetation by endemic species

No specifically defined land use

•

Species that rapidly stabilize the site, including commercial grass varieties

Nature conservation

•

Maximize floral diversity in accordance with original ecosystem

Recreation

Agriculture or grazing

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species. The problem of erosion can be minimized by channelling runoff away from the area to be revegetated, and by firstly stabilizing the area with grasses and other forms of rapidly colonizing groundcover, before establishing larger shrubs and trees.

Selection of suitable species for revegetation A number of taxa in Finland are well adapted to relatively acidic natural conditions, including grasses of the family Poaceae, such as Deschampsia flexuosa (wavy hair-grass), and members of the Polygonaceae, Caryophyllaceae and Asteraceae, including the common sorrel (Rumex acetosa), sticky catchfly (Lychnis viscaria) and golden rod (Solidago virgaurea). Some conifers and herbaceous and woody shrubs are also tolerant of relatively low pH soils (Karjalainen 1993), although the majority of plants used in site revegetation are best suited to pH levels in the range 5–7. Most species are also tolerant of modest amounts of soil contaminants, with trees in particular being able to survive anomalous concentrations up to 2 orders of magnitude above background levels (Dickinson et al. 2000). Other plants that are resistant to elevated substrate trace metal concentrations include the grasses of the Poaceae family, Festuca ovina (sheep’s fescue), and F. rubra (red fescue), and members of the genus Agrostis, notably A. capillaries (colonial bentgrass), as well as the common sorrel (Rumex acetosa), Deschampsia cespitosa (tussock grass) and Anthoxanthum odoratum (sweet vernal grass). Other tolerant taxa include plantains (Plantago spp.), field penny-cress (Thlaspi arvense) and sea sandwort (Honckenya peploide). The alpine catchfly (Lychnis alpina) appears to be particularly tolerant of elevated copper abundances, while the common ox eye daisy (Leucanthemum vulgare) and yarrow (Achillea millefolium) are suited to a wide range of conditions. The first tree species to colonize tailings and waste rock piles are typically birches (Betula spp.), willows (Salix spp.), and aspen (Populus tremula) (Figure 46). Replanting programs in Finland should ideally be of mixed species, including spruce (Picea abies) and birch (Betula spp.), interspersed with scattered rowan (Sorbus aucuparia). It is important that root systems do not penetrate too deeply, so as to avoid significant disturbance to soil structure, or infiltration of oxygen and water. For these reasons, aspen (Populus tremula), alder (Alnus spp.), pine (Pinus sylvestris) and members of the willow family (Salicaceae) are not recommended (Naturvårdsverket 2002). Conversely, the fact that these species have deep root systems makes them ultimately more resilient. Moreover, roots systems of pine trees are known to sequester at least lead and arMine Closure Handbook P. M. Heikkinen, P. Noras and R. Salminen (eds.)

senic, thus potentially reducing the bioavailability of these elements. Revegetation of steeper slopes can be facilitated by the use of mulch or other binding agents and the construction of terraces and retaining walls to prevent erosion. In such situations, willows (Salix spp. and Populus spp.) and alders (Alnus spp.) are ideal, since their efficient evapotranspiration also acts against water infiltration and may thus reduce erosion. Other plants that are similarly effective in water uptake are clovers (Trifolium spp.), wood angelica (Angelica sylvestris), coltsfoot (Tussilago farfara), and the common clubrush (Schoenoplectus lacustris).

Optimizing conditions for revegetation The lack of nutrients in reclaimed ground may be addressed by addition of slow release chemical and organic fertilizers, while pH may be increased through the use of lime. Legumes, such as lucerne (Medicago sativa), clovers (Trifolium spp.), vetches (Vicia spp.), and lupins (Lupinus spp.) can also be used to permanently enhance nitrogen levels in soil, although these species tend to be sensitive to pH levels less than 6.0. In some situations it may be possible to plant directly on waste rocks or tailings, by covering them with a thin veneer of mulch or compost or by using species that are especially tolerant to elevated metal concentrations. Under more demanding circumstances, it may be necessary to spread a layer of topsoil first. However, if this layer consists primarily of clay and peat, it will be vulnerable to excessive drying in the summer months. Therefore the substrate should ideally be both more water-retentive and enhance stabilization, and of sufficient thickness to deal with susceptibility to erosion and depth of root penetration.

The use of vegetation in soil rehabilitation Vegetation can also be used in the remediation of degraded or contaminated soil. Several plants can decrease the number of contaminants in soil and their transport by breakdown or through uptake either into root systems below ground or woody tissue and foliage above ground. The potential for this approach is widely recognized, although as yet there are no clearly defined guidelines in place. It is therefore recommended that site-specific pilot investigations should be undertaken wherever possible. The use of vegetation may be appropriate in mitigating the effects of certain metals, petroleum-based products, chlorinated hydrocarbons, and PAH compounds, providing that the following factors are taken into consideration:


Figure 46. Progressive colonization of reclaimed tailings area by birch (Betula spp.), willow (Salix spp.), Scots pine (Pinus sylvestris) and various grasses. Where conditions for regrowth are less favourable, an extra layer of topsoil may be needed.

• The site in question needs to be well characterized in terms of hazardous compounds and their respective concentrations, soil pH, nutrients and organic matter content, the nature and proximity of surrounding activities and prevailing light intensity and aspect, moisture conditions and wind patterns. • Plants must be selected which are appropriate for both the types of hazardous compounds and anticipated growing conditions. Recommended species include the willows (Salicaceae), field penny-cress (Thlaspi arvense), dandelions (Taraxacum officinale), common ragweed (Ambrosia artemisiifolia), red-root amaranth (Amaranthus retroflexus), aspens and poplars (Populus spp.), wild mustard (Sinapis arvensis), sunflowers (Helianthus annuus), and clover (Trifolium spp.). • Root systems must not form pathways for water infiltration and metal transport. • Ensuring that the addition of fertilizer does not lead to changes in pH that might liberate or leach metals or other hazardous compounds. • Plants that accumulate hazardous compounds can be periodically cut or removed from the reclamation site, which may therefore require additional disposal in a designated hazardous waste facility.

A checklist outlining strategies for designing and implementing revegetation programs is presented in Appendix 17.

107

6.3 POST-CLOSURE LAND USE AND TRANSFER OF OWNERSHIP 6.3.1 Alternative options for land use following mine closure The mine operator commonly retains the land ownership rights on a mining concession after mining activities have ceased, unless there is a compelling reason for all or part of the area to be sold. While open pits, tailings impoundments and areas prone to subsidence are subject to environmental monitoring and risk management, the mine operator is still responsible for the area and it is therefore advisable to relinquish ownership only when the mine site is considered to pose no environmental or safety risk. Even then it is normal practice for certain fenced off areas, such as pits susceptible to slope failure and rock falls, or in some cases tailings impoundments, to remain as the permanent property of the last operator of the mine. In contrast, land suited to agricultural purposes, with the exception of areas that may have been affected by contamination, is usually sold. If possible, any mine infrastructure

that remains after decommissioning can be used by other businesses and industries, which also requires that roads in the mine area are upgraded or modified for improved public access. Depending on location, the former mine site can be developed to suit a variety of recreational uses. For example, in Finland, the tailings area at the former Keretti mine has now become the Outokumpu golf course (Figure 47), while the former tailings impoundment of the Virtasalmi mine now serves as a racing track. If the mine operator does not actually own the land, the area of the mining concession reverts to the original owner as soon as the operator relinquishes mining rights (Mining Act, Section 51). In such circumstances it is recommended that negotiations concerning future land use options and possible restrictions involve local municipal authorities as well as the mine operator and landowner. It is also advisable to reach a formal agreement on potential land use restrictions where the mine operator sells all or part of the land to an outside party. Particular attention should be given to tailings

Figure 47. After landscaping and rehabilitation, the former tailings impoundment of the Keretti mine (Finland), now functions as the Outokumpu golf course.

108


impoundments and waste rock disposal sites, to areas subject to collapse or slope failure, and any earthworks or drainage systems related to water containment, channelling and treatment. A written contract should be drafted between both or all parties, clearly defining proposed activities, any areas to be excluded, and a mutual agreement apportioning responsibility and accountability for safety and environmental issues. The contract may also specify that any excavation, quarrying, or earthworks carried out within the former mine area must be negotiated with the last mine operator. Local government planning authorities also have the right to impose building or land use restrictions at the site and register it into the local building code, should this be deemed necessary (cf. Section 3.5).

6.3.2 Relinquishment and transfer of ownership and liability

for example, responsibility for preventative measures against environmental or safety risks, remediation of contaminated soil, or for removal of waste from the site, in a way which could be seen as binding with respect to regulatory and other authorities. It is advisable for both parties to agree on who will be liable in the event of future pollution of soil or groundwater, which can be directly attributed to materials or actions related to mining activity (cf. Section 3.2). It must be noted that an exemption clause of this nature is only binding for the parties to the agreement, and that supervising authorities may intervene and assign responsibility as is deemed appropriate. It is also important to agree on a course of action, if the extent of contamination proves to be greater than the estimate made at the time of drafting the contract, and how both anticipated and unforeseen expenses will be shared. It is also advisable to define an upper limit for expenditure, and to agree on a course of action if this limit is exceeded.

Relinquishing operating rights When the rights to conduct mining activity are transferred to another operator, the transaction must be recorded in the original mining certificate. The new custodian, or party responsible for negotiating the transfer, is then required to inform the Ministry of Trade and Industry within 60 days, so that the change of ownership can be duly recorded in the mining register. The transfer of ownership becomes legally binding from the date that the Ministry of Trade and Industry receives written notification of the transaction, although in the case of a bona fide third party, the transfer becomes valid from the date of entry in the register (Mining Act, Section 54). The new custodian is further required to inform the Ministry of the Environment of the transfer of ownership and environmental permits (Environmental Protection Act, Section 81). Responsibility for any adverse environmental impact at the mine site (excluding that caused by any activities prior to 1.6.1995), is also transferred to the new operator if he or she was aware of, or should have been aware of, the problem when the transfer of ownership took place (Environmental Protection Act, Section 7). It is advisable to commission an environmental due diligence survey prior to relinquishing mining rights, as in transferring ownership of real estate. A formal contract drawn up between the two parties, also enables mutual responsibilities to be agreed upon, such as liability for specified activities carried out at the site or exemption of certain areas from the agreement restriction although under common law such agreements are not binding with respect to third parties. Likewise, it is normally not possible to transfer any statutory obligations under the Environmental Protection Act, Environmental Techniques for the Extractive Industries

Relinquishing title to land, buildings and infrastructure Transfer of title and ownership on relinquishment must comply with the Environmental Protection Act and the Real Estate Code (540/1995), including the requirement for accurate reporting of the state of the site by the seller (Environmental Protection Act, Section 104) and, subject to certain conditions, responsibilities that the new title holder may have for any future site remediation activities (Environmental Protection Act, Section 75). The previous title holder, whether operating the mine as a landowner or under a leasing arrangement, must provide a report to the new title holder or owner, detailing all activities carried out at the site, with a comprehensive description of all materials and waste that has the potential to cause contamination of soil or groundwater. The purchaser, or new title holder, is also responsible for obtaining all available information concerning previous operations and potential environmental, health, and safety risks at the site. The new owner may actually be liable for remediation and reasonable compensation, if it can be shown that he or she knew, or should have been aware of, potential risks at the site at the time of transfer of title and ownership (Environmental Protection Act, Section 75). According the Real Estate Code, parties to the transfer of ownership must reach agreement concerning the precise nature and contents of the sale. If a discrepancy between the contents of the document and the actual real estate is subsequently found, and an error of omission is acknowledged, negotiations are required to establish which aspects of the omission can be interpreted as agreed to in the sale and

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which can be otherwise agreed upon. Depending on its severity, and whether the extent was acknowledged at the time of signing the contract, site contamination may be viewed as a serious hidden or quality defect under Section 17 of the Real Estate Code. The seller is required to provide information that is both accurate and sufficient concerning the nature and quality of the real estate involved in the transaction, including any hidden factors which might conceivably affect overall value. Conversely, the buyer cannot appeal to ignorance with respect to a particular defect or omission, if it falls into the category of matters which any responsible title holder should be aware of. The nature and extent of possible defects is determined according to the condition of the real estate at the time of sale, which means that the seller is responsible for the consequences of any defect which existed at the time of sale, even if it were not evident at the time (Real Estate Code, Section 21). The buyer is similarly obliged to investigate and document the condition of the real estate prior to the sale and cannot interpret a problem as a defect if it is clear that it was recognized and acknowledged at the time of sale (Real Estate Code, Section 22). The possibility of unidentified contamination being present at the site, and the cost of any investigations and remediation that might subsequently be required, can, however, be made a condition of sale.

Transactions and mergers Relinquishment of corporate ownership is more complex, and may involve direct transfer of shares, consolidation through company mergers and acquisitions, or alternatively divestment of assets and establishment of subsidiary companies. Transfer of shares, in part or entirety, is usually straightforward with respect to existing permitting commitments and obligations; as the new title holder remains a distinct legal entity under corporate law, there is no effective change from the perspective of regulatory authorities. Corporate mergers do not necessarily cause disruption to permitting obligations either, since the companies involved in the amalgamation are replaced by a newly defined company that assumes responsibility. Company mergers may also take place such that shares are held in joint ownership. In this case the existing company structures are retained as legal entities, until such time as a formal merger is implemented, and from a legal perspective this arrangement does not differ from that involving direct transfer of shares. From the viewpoint of permitting and regulatory authorities, procedures during partitioning or diffusion of a larger corporation into smaller companies resemble relinquishment of business activities, in that it generally unites a broad but related range of activities

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under the collective responsibility of a single legally defined company. Under these circumstances, the new title holder is required under Section 81 of the Environmental Protection Act to inform the relevant authorities of the transfer of ownership. From the perspective of the Mining Act, the transfer of ownership to such a company is classified as a transaction which needs to be entered in the mining register.

Financial security and solvency issues In the event of bankruptcy of the mine operator, the company board is replaced by a body of trustees appointed to act on behalf of the company. If a decision is not made to immediately sell all assets related to mining activity, or if the trustees do not decide in favour of continuing mining operations, then standard mine closure procedures, obligations, and strategies will apply as normal. Insolvency issues nevertheless inherently contain a degree of uncertainty and it is, therefore, advisable for the trustees administering the mine, either on their own initiative, or in conjunction with relevant authorities, to reassess the most important issues relating to permitting and environmental and safety responsibilities. Safety issues are dealt with by the Safety Technology Authority of Finland and require a commitment to maintaining safety standards at the site and regular inspections. Obligations and responses required under environmental legislation need to be established and agreed upon in consultation between the administrators and relevant authorities. Separate inspections may be carried out by officers from the appropriate Regional Environment Centres, after which report should be prepared, defining those issues requiring immediate attention and for example, a revised ongoing monitoring and due diligence plan. Should the trustees decide in favour of continuing business operations, there is also an ongoing obligation to meet environmental legislation requirements. The estate under the administration of the trustees must, therefore, assume responsibility for any contamination resulting from continued activities and for arranging appropriate management of waste. The total assets and liabilities of the bankruptcy estate must also be declared, as well as the level of insurance taken out and the amount of any pledged collateral or guarantees. After judgment has been officially handed down concerning the value and distribution of estate assets, the trustees can ascertain the resources available for any closure-related procedures that might be necessary, such as fencing or excavation and removal of contaminated material, or for post-closure site monitoring. However, it is not possible to assign funds from the estate specifically for remediation of contaminated Mine Closure Handbook P. M. Heikkinen, P. Noras and R. Salminen (eds.)

soil or groundwater, if no separate guarantees exist, or if they are considered inadequate to cover remediation costs. It is therefore important that bankruptcy proceedings are attended by an appropriate representative of the government, to ensure that financial provisions are sufficient to meet any such obligations. The mine operator, as the holder of a permit as defined in law, is required to allocate a specified amount of money, in proportion to total company turnover, as a contribution towards insurance against environmental risk or damage (Environmental Damage Insurance Act 81/1998). Funds received in this way are intended for use in compensation for environmental incidents and damage, in cases, where the perpetrator is unknown, or financially insolvent.

Land tenure after the operations If custodianship of the mining concession reverts to the landowner from whom it was leased during mining, then any equipment or facilities remaining on site after a period of two years has elapsed, automatically becomes the property of the landowner, as discussed in Sections 6.1.6 and 6.1.7 (of the Finnish Mining Act, Section 51). According to both the Mining Act and legislation covering damage liability (Tort Liability

Act 412/1974), the mine operator remains responsible for any damage related to mining activities. If contamination due to mining is observed at the site after closure and relinquishment, but there is no longer any mine operator to assume responsibility, the current landowner may be liable for compensation and implementation of remedial measures, simply on the basis of ownership status. However, it appears, when considering the outcome of past legal proceedings and individual examples, that prosecution of the landowner in such cases would be highly improbable. Regulations concerning contaminated soil are described in more detail in Section 3.2.

Insurance against post-closure environmental damage Although it is possible to take out insurance against the possibility of environmental damage during or postclosure, in practice this may prove to be prohibitively expensive. While the general intent of insurance would be to cover compensation for damage or contamination due to an unanticipated event or accident, in reality most environmental problems are seen to be a consequence of longer term activity.

6.4. INFORMING REGULATORY AUTHORITIES AND THE GENERAL PUBLIC CONCERNING MINE CLOSURE Mine operators generally have a preferred option for communicating to the public and stakeholders concerning developments or changes, and the issue of mine closure can be dealt with in the same way. While there is no legislative requirement for informing the general public of mine closure, the operator may be guided by a company public relations and environmental policy that favours transparent engagement with the surrounding community and regulatory authorities. There are, however, some additional statutory obligations, (for example under the Accounting Act 1336/1997, and Companies Act 734/1978) to inform various stakeholders, such as shareholders, auditors, employees, concerning closure and relinquishment plans, and any attendant changes in company operations or ownership. A distinction is made here between general comments made in public and official applications, proposals and statements submitted to regulatory authorities and other third parties, in compliance with legal


commitments, or to stakeholders (“… whose interests and rights may be affected by …”), and employee representatives or others who are affected by company decisions (“… opportunity to express opinions on proposed…”). Section 3.6 provides more detailed information on requirements and procedures in relation to regulatory authorities. It may be necessary to have a statement drafted and issued according to a standard procedure and format under official or legal guidance. If the statement or submission process is incomplete or misleading, there may be a delayed response or requirement for resubmission, if not outright rejection. The mine operator may also concurrently issue separate statements of a public nature, in relations to proposed activities and mine closure, but must take care to ensure that a clear distinction is made between formal negotiation process and informal public announcements.

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7. MONITORING OF MINE SITE REHABILITATION PROGRAMS – REQUIREMENTS AND PROCEDURES

The primary reason for ongoing monitoring of the mine site following closure is to ensure that remediation measures, including earthworks, water treatment, and drainage systems, function as intended and in accordance with closure criteria. In addition, site surveillance may be necessary to demonstrate that the mine site remains safe and poses no environmental or health risks. Regular monitoring also allows for a proactive response where the rehabilitation process is found to be deficient, or in the event of structural failure. Mandatory monitoring requirements during active mining, as well as following cessation of operations and closure, are specified in environmental legislation (refer to Section 3.1.3). The type of monitoring required is determined at each mine according to the specific nature of the mining process, with an appropriate emphasis on those issues, which the risk assessment process has identified as potentially problematic in terms of either safety or contamination. For example, if it can be demonstrated that discharge from waste rock areas or tailings is unlikely to represent a contamination risk, it is generally not necessary to keep water quality at the site under close surveillance. Instead, the monitoring program may focus on the structural integrity and stability of the tailings impoundment. Typical features that can be routinely monitored following closure may include: • the state of fencing and warning and prohibition signs, • the stability of embankments and tailings impoundments and other areas potentially subject to slope failure, • flooding of the mine workings and evolution of water quality, • chemical stability of tailings and waste rocks, evaluation of the success of the assessment of their longterm behaviour, and the long-term performance of the applied wet/dry covers, • functionality of water treatment and drainages systems, and • success of revegetation programs.

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Each of these features may be monitored based on the following attributes and procedures: • visual inspection of embankments and tailings impoundments, assessing extent of erosion or changes in morphology and water level, • measuring volumes and quality of water discharge from tailings areas and waste rock disposal sites, • measurement of physical and chemical parameters of surficial waters both upstream from the mine and at downstream discharge sites, • assessing state and viability of surrounding aquatic ecosystem, including measurement of physical and chemical properties of water, • physical and chemical characterization of groundwaters in surrounding watershed, and • monitor revegetation rates, biodiversity and density of vegetation cover.

A comprehensive monitoring plan should be drafted, at the latest in conjunction with the final closure plan, for submission to the relevant environmental authorities. Some elements of the monitoring program will inevitably be based on the requirements and recommendations contained within environmental permits. Final details will however, vary according to specific assessment of environmental impacts at a given mine and the most appropriate remedial measures. It is advisable to consult with local environmental authorities concerning the main features of the envisaged monitoring plan and attendant procedures, prior to formal drafting and submission. A typical monitoring program accompanying a mine closure plan would include features such as: • what is to be monitored (what processes are being measured; what variables are being monitored), • how is monitoring implemented (sampling and analytical techniques used in monitoring), • a description of establishing and maintaining a followup system or surveillance network, • frequency of monitoring (schedules and timing of sampling intervals),


• duration of monitoring (estimate of total time required), and • responsibility for monitoring (who will undertake the monitoring and ensure compliance).

The following sections provide specific and detailed examples of planning and implementation of post-closure monitoring of surficial and groundwater quality and geotechnical specifications for mine embankments and tailings and waste rock areas.

7.1 POST-CLOSURE MONITORING OF SURFACE WATER AND GROUNDWATER The underlying aim of monitoring surface water and groundwater quality after mine closure is to ensure that there is no pollutant discharge into the surrounding environment or, if contamination does occur, to facilitate rapid detection and response, thereby minimizing any adverse health and environmental consequences. Monitoring also provides valuable reference data for authorities in subsequent decision-making and in refining environmental permitting procedures or land use planning. The requirement for monitoring water quality may be negotiated on a case-by-case basis, if for example, it can be demonstrated that mining activities do not adversely affect water in surrounding areas. However, when planning monitoring strategies in areas where closure is imminent, or where operations have already ceased, it is essential that adequate background information is available. In general this requires knowledge of the following: • precise extent and boundaries of surrounding catchment areas; • nature of bedrock, including rock types, and characterization of faults and fracture zones in terms of location, orientation and extent; • surficial and regolith geology, including thickness of overburden, stratigraphy, results of any additional regional studies such as drilling or geophysical, seismic and radar surveys; • precipitation; • location of surface water bodies, including lakes and wetlands, rivers and streams; • whether or not the area contains significant aquifers and is classified, or protected, as a source of groundwater (Britschgi & Gustafsson 1996); • hydrology of surface drainage, extent of watershed which may potentially be affected by mine water outflow, absolute amounts and potential variations in volume of water bodies (refer to Section 4.1.1); • seasonal fluctuations in depth and absolute range of groundwater table, and possible variations in groundwater flow paths; • location of groundwater discharge zones, with flow


•

•

•

•

rates, and locations of groundwater monitoring sites and wells; results of groundwater investigations carried out in the area, including reports relating to the installation of observation wells and information concerning flow rates during pumping tests; chemical composition of water, including data on seasonal variations and sampling under variable climatic conditions, as well as data on surface and groundwater samples from different sources and depths; documentation of the status of water prior to commencement of mining and any changes observed during mining, and usage of surface and groundwater in proximity to the mine site, including surface storage or groundwater extraction, either for nearby communities or for individual households.

The nature of post-closure water treatment and drainage systems and processes affecting the composition of mine waters throughout the mine site, but particularly in relation to tailings and waste rock areas, should be understood prior to preparation of the monitoring plan. The number and locations of monitoring and sampling sites required for groundwater investigations are determined by local hydrological conditions and the relative importance of the area with respect to groundwater recharge and storage. Furthermore, the possibility of whether or not aquifers are exploited for domestic or other forms of consumption has to be taken into account. Monitoring of surface waters should be carried out both upstream from the mine site, to determine baseline levels, and downstream of discharge sites. In practice, this usually means sampling from streams flowing through the mine site, or from drainage systems and channels designed to capture all surface waters at the site (Hatakka & Heikkinen 2005). A comprehensive description of methods for investigating groundwaters can be found in a manual published by the Water Association Finland (Suomen Vesiyhdistys 2005). Groundwater volumes are estimated and monitored from productivity/yield- and

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Figure 48. Groundwater samples for monitoring purposes can be taken from (a) existing domestic wells, or (b) from observation wells.

flow-rate measurements made at selected discharge sites, combined with water table data from specifically drilled observation wells and existing productive wells. Groundwater quality can be monitored by sampling from natural springs and productive or observation wells (Figure 48). All sampling sites should meet standard requirements with respect to their general condition and material properties in order to ensure representative sampling. If there are no suitable observation wells in the area, sufficiently dense network of observation wells must be established, with careful attention given to installation, construction and documentation. Depth of observation wells varies according to local site conditions but it is usual to penetrate as far as the bedrock interface, with the screened interval including the entire depth of groundwater body. The natural fluctuations of the water table must be taken into account before installing the screen. It is also important to consider both the pipe diameter and material composition; the inner diameter of the observation well should be sufficient enough to allow insertion of standard measuring and sampling instruments, for example, pumps with sufficient suc-

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tion capability. Likewise, the pipe must be made of an inert material to avoid sample contamination. In some cases, groundwater monitoring may include sampling from wells drilled into bedrock, especially if these are used as domestic water sources, or if the bedrock is highly fractured and the possibility of infiltration by contaminated mine waters is suspected. The most relevant parameters for analysis and measurement are generally determined on the basis of previous investigations, but may also include some additional variables that relate more specifically to environmental risks identified at the site. In addition to assessing the presence of specific contaminants, the monitoring program can also involve measuring variables which affect metal solubility, such as pH and dissolved oxygen, chlorides, sulphates and nitrates. The range of variables chosen for analysis depends on site-specific conditions and circumstances. Comprehensive analysis of water chemistry should ideally be repeated on an annual basis, even though only few metals are present in anomalous concentrations. Chemical analysis of surface water may be supplemented by monitoring of biological indicators. Mine Closure Handbook P. M. Heikkinen, P. Noras and R. Salminen (eds.)

Figure 49. Following mine closure, monitoring of surface and groundwater quality involves in situ measurement of certain parameters, such as pH, electrical conductivity and oxygen, in addition to laboratory analyses.

It is recommended that certified personnel (SFS-EN ISO/IEC 17024) collect samples using appropriate and approved methods. Careful documentation of the sampling procedure is necessary to ensure reproducibility and verification of time series comparisons. Samples should be analyzed in an independent accredited laboratory using officially certified procedures. However, for some parameters, such as pH and electrical conductivity, the most reliable results are obtained by in situ measurement at the field (Figure 49, and see also Paukola et al. 1999 and Suomen Vesiyhdistys 2005). The level of the water table and discharge are also routinely measured in connection with sampling. Surface water samples can be taken using bailers beneath the surface or by retrieving a suite of samples from different depths (see also Mäkelä et al. 1992). The pumps used in groundwater sampling from observation wells need to be sufficiently efficient. In case the monitoring site consists of soils with low permeability, it may be necessary to pump the observation wells dry a day or so prior to sampling, in order to obtain samples from fresh water. In such cases the samples are usually taken using bailers. It is also advisable to collect duplicate and blank samples for quality control purposes. The proposed sampling strategy should also be included within Environmental Techniques for the Extractive Industries

the monitoring plan submitted to the environmental authorities. Sampling frequency will vary depending on site-specific hydrology and is, therefore, determined on a case-by-case basis. If the area includes significant groundwater resources supplying surrounding communities, or if there are individual wells and natural springs used by households in the immediate vicinity, sampling should be undertaken on at least a quarterly basis. Seasonal variations are also monitored by taking samples during spring maxima, summer minima, autumn maxima, and winter minima. In Finland this means sampling during February–March, May–June, August–September and November–December. If there has been previous indication of deterioration in yield or quality of well water, sampling should be undertaken more frequently and extended to include all wells that might conceivably be subject to contamination or flow disturbance. If, however, the area surrounding the mine site is uninhabited, and not used for any other commercial or recreational activities, less frequent monitoring is sufficient. Even then, however, sampling should be undertaken at least twice a year, preferably so as to coincide with the spring maximum in May-June and summer minimum in August-September. If there is no human activity whatsoever in the area, sampling on an annual basis may be adequate. If the rehabilitation site is in proximity to areas listed for protection under the Natura 2000 program, such as wetlands and springs, consultation concerning more stringent monitoring is inevitably required. Sampling frequency of surface waters varies according to choice of parameters. According to the European Water Framework Directive (2000/60/EC), biological parameters should be measured at intervals varying from 0.5–3 years, while physical and chemical parameters should be monitored more frequently, at intervals of 1–3 months (European Parliament and Commission, 2000, Appendix V, Section 1.3.4). These monitoring guidelines are however negotiable, if it can be shown that the reliability and precision of site surveillance will not be compromised by less frequent sampling. Although statutory limits can not be imposed for the duration of mine site surface water and groundwater monitoring programs, in each case a specific timeframe can nevertheless be stipulated, after which the situation is subject to further review. If, during systematic monitoring over a period of at least 3-5 years, there are no detectable adverse effects on surrounding water quality, then the frequency of monitoring may be reduced. Conversely, if appreciable changes in water quality or yield are observed, surveillance requirements may need to be reassessed. A comprehensive list of guidelines and procedures for systematic monitoring of surface and groundwaters is given in Appendix 17.

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7.2 GEOTECHNICAL SURVEILLANCE OF MINE EMBANKMENTS AND TAILINGS AREAS The purpose of systematic geotechnical monitoring at the mine, following closure, is to ensure that the structural integrity of earthworks is maintained according to plan, and that potential risk factors are identified in time to initiate an appropriate response. Design of a geotechnical monitoring plan should be undertaken by an accredited professional specialised in construction of mine embankments and impoundments. To a large extent, post-closure surveillance is a continuation of monitoring processes initiated during mining activities, ensuring that earthworks are constructed in a stable manner. Therefore, monitoring criteria developed during mining can usually be applied to the post-closure phase as well. Typical features included for regular and routine assessment in such surveillance programs include: • visual inspection of the overall mine site and earthen structures • assessment of the level of pore waters and surface waters • determination of pore water content and seepage in embankments and other earthworks • measurements of potential surface deformation, mass movement or failure.

• effectiveness of drainage systems, including state of open channels, • success of slope stabilization by vegetation cover (plant survival and growth, extent of cover, presence of oversize trees), • evidence of surface subsidence or cracking and breaching of tailings covers • effectiveness of drainage and drying procedures in tailings covers • effectiveness of vegetation colonization of tailings covers

Visual inspection and comparisons of changes over time may be facilitated by filming or photographing the site. After mining operations have ceased, systematic measurement of pore water levels and pressures is necessary along profiles through embankments and retaining barriers, while groundwater discharge can be measured by installation of specifically designed water gauges (Figure 50). Measurements are primarily

The monitoring program needs to be designed specifically to meet the attributes and remediation requirements of individual mines. Qualitative visual inspection includes: 1) Inspections of a general nature • general condition of fencing enclosing the site, and • general condition and functionality of monitoring equipment. 2) Open pits and waste rock disposal areas • evidence for erosion or mass movement and slumping of sloping embankments and retaining barriers, and • effectiveness of measures implemented for draining and drying the mine site. 3) Embankments and impoundments • evidence for slope instability and creep at the base of embankments and retaining barriers, • evidence of erosion of embankments by surface water overflow or pore water seepage, • evidence of differential compaction and cracking or fissuring in terraces and embankments,

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Figure 50. Seepage water discharge rates from waste rock areas and tailings impoundments can be monitored effectively by installation of standard V-shaped water gauges (Vee-weir) at outflow locations.


made from the existing observation points, but depending on the requirements of the monitoring plan, it may prove necessary to increase the number of measuring points. For example, where tailings impoundments are only covered in part (with the central area remaining exposed), it is likely that the groundwater level will be lowered towards the embankment margins. It is, therefore, recommended that monitoring instruments are installed along at least one profile across the covered part of the impoundment, as well as on the embankment slope. To monitor the behaviour of pore water levels over time, and anticipate potential lateral mass movement, it is advisable to install borehole inclinometers along one or two profiles across the embankment, in which the safety factors are lowest. Practical procedures for installing and using inclinometer are described in the report published by the Finnish Road Administration (Tiehallinto 2000). It is both advisable and practical to perform visual inspections concurrently with more quantitative monitoring methods, such as pore pressure measurements. At the Hitura nickel mine, for example, it has been customary in recent years to determine pore pressures within embankments and barriers at a rate of ten times per year. Accordingly, it might be anticipated that at least during the initial stages of the post-closure monitoring program at Hitura, qualitative visual inspections would be carried out at monthly intervals. It is also necessary to assess the integrity of earthen structures immediately after exceptional rainfall events. Frequency of monitoring should also be greater during and immediately after construction of embankments and other earthworks, and while covering tailings impoundments. Progress of water filling abandoned


open pits and workings should also be subject to close surveillance until conditions approach a dynamic equilibrium. As waste rock areas, embankments and other structures progressively stabilize, monitoring frequency can be steadily decreased such that waste rock disposal sites that have shown no evidence of surface deformation or slope failure over extended periods, and which are not subjected to further loading during closure, need only sporadic monitoring. Further specific recommendations concerning nature and frequency of site surveillance following closure are given in the EC’s BAT reference document (EC 2004). All instruments deployed in the field during the monitoring program should be clearly marked and protected for accidental or deliberate interference and damage. In the case of monitoring surface deformation and mass movement, it is also necessary to ensure that benchmarks and survey points still remain in place and accessible after site monitoring has ceased. The precise locations of monitoring systems must be documented carefully, as well as the results of measurements, and recorded in notebooks and databases. It is desirable to present results in graphical format as well, to allow evaluation of changes in material parameters and behaviour along specific profiles over time. Such an approach allows potential departures from expected behaviour to be identified at an early stage and hence to anticipate the need for any further risk management and mitigation. To ensure that this process is effective, regular inspection and appraisal of surveillance results by a nominated person is required. A detailed list of criteria and procedures for monitoring geotechnical stability of earthworks and other structures is outlined in Appendix 17.

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8. RESERVE PROCEDURE, PLEDGING A GUARANTEE AND COST ESTIMATES IN MINE CLOSURE

A mine closure cost estimate contains the costs of the component actions included in the closure plan and the cost effects of implementing the entire plan. For the mining company, the mine closure costs constitute a significant item over the life-cycle of a mine. Funding a mine closure by entering annual reserves in the balance sheet is consistent with good reporting and closure practice. The purpose of entering these reserves is to ensure that mine closure costs have been taken into account as accurately as possible in the company’s bookkeeping so as to avoid the costs being too much of a financial burden on the company towards the end of the mine’s life-cycle, at which time the profitability of the mine tends to be decreasing too. Both voluntary and compulsory reserves entered in the final accounts are used. The environmental permit procedure (Environmental Protection Act, Section 42, and 1999/31/EC) requires that a guarantee be pledged to ensure waste management. In the extraction industry, this usually applies to actions taken at closure regarding the disposal areas for tailings and waste rock classified as waste. The main purpose of the guarantee is to ensure that society can cover the costs of normal waste management measures foreseen at the moment of the environmental permit being granted, in case of the insolvency of the operator. The guarantee is pledged to the environmental permit authority or the supervising authority. The guarantees required have ranged from less than one to dozens of Euros per square metre of tailings area. The size of the guarantee, its accumulation, the inspection interval, dismantling of the deposit or guarantee, and the specific arrangement of the guarantee vary by site, area and depending on the solvency of the operator. It should be noted that a reserve in bookkeeping, even a compulsory reserve (Accounting Act 1336/1997, Section 5.14), is not accepted as a guarantee in this sense; it must be a bank deposit, an absolute guarantee, guarantee insurance, etc. The guarantee is dismantled once the aftercare actions have been acceptably completed. Part of the guarantee may be withheld for unforeseen future work (see Ministry of the Environment instruc-

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tions, Dnro YM2/401/2003, Kauppila & Kosola 2005, and Section 3.1.1). The guarantee procedure causes indirect additional costs to the company due to reduced borrowing potential and possibly increased loan management costs. The procedure has been in use in Finland only for a few years, and there is as yet no accurate conception of its details, its indirect cost impact on companies, or recommended bookkeeping practices (see Appendix 5). A closure plan drawn up at the beginning of the life-cycle of a mine is, naturally, fairly inaccurate, and thus the related cost estimate is also inaccurate. Accordingly, the costs should be regularly reappraised as mine operations progress, as processes develop, as statutory objectives change, as environmental investments affecting closure costs are being made, and as prices change. Costs are dependent in many ways on the location of the production and the production processes: the target state of closure, land use, the physical and chemical properties and volumes of the waste rock and tailings, material processing problems, etc. The cost variance depends on the level of reliability or certainty sought; this variance can be significantly reduced by using risk management methods to identify and prioritize uncertainties. The risk management costs of low risks are usually reasonable, and the cost variance may be +/- 25% or 30%. The risk management costs of high risks are not only higher but more difficult to estimate too, and the cost variance may be +/- 100% or even more. In the following, it will be summarized how the cost responsible body is determined, and how the closure costs are roughly estimated and scheduled. These are indicative and tentative examples; individual cases may differ greatly. The estimates given are based on the closure of a medium-sized sulphide ore mine in Finland.

Responsibilities The costs of mine closure are the responsibility of the last mine operator or the owner of the area if ownership of the area is transferred when mine operations Mine Closure Handbook P. M. Heikkinen, P. Noras and R. Salminen (eds.)

are discontinued. The mine operator may be liable for aftercare costs if the new owner is unable to fulfil his responsibilities. It should be noted that the guarantee procedure only covers the rehabilitation of the disposal areas for waste rock and tailings classified as waste.

Cost timing The major closure costs are usually caused by actions that cannot be taken before the mine operations are discontinued. A rough estimate is that only about 10% of the costs of closure are realized while the mine is in operation, while 50% to 60% of the costs are realized during two or three years following the discontinuation of operations, the remaining 30% or 40% being distributed over the following several years, depending on the site. Nevertheless, variances of the given figures may be considerable.

Cost by measure The largest costs are usually caused by the covering of the tailings area. Depending on the structure of the covering layer, the availability of the material and the location of the site, the costs may be between EUR 5,000 and EUR 25,000 per hectare and may constitute up to 50% to 75% of all closure costs. Significant cost variance in earthwork can be introduced by cyclical fluctuations in the construction market and the location of the mine. Demolishing a concentrator costs between EUR 100,000 and 300,000, depending on its size and the price, and volume of recyclable scrap. In some cases, the value of the scrap steel alone is enough to offset the cost of demolition. Other structures may cost EUR 50,000 to 200,000 to dismantle and move. Tidying up the site and disposing of demolition materials cost EUR 100,000 to 200,000, while water treatment arrangements may cost EUR 50,000 to 200,000 depending on the water quality and local conditions. Further costs can be caused by the rehabilitation of the soil in the concentrator and industrial areas. The cost of dismantling the mine itself is EUR 100,000 to 400,000 depending on the equipment to be


removed, tunnels to be filled in, and access holes to be closed. Open pit closure involves evening out slopes, dismantling equipment and structures, and erecting a fence. The shaping and possible covering of waste rock piles is also a significant expense, totalling some EUR 1,000 to 20,000 per hectare. Mine closure may also require several official permits which may cost EUR 10,000 to 30,000 to obtain. Fulfilling the permit requirements may sometimes require further investigations, which can easily cost EUR 50,000 to 100,000 depending on their extent. Personnel costs depend on the number of people dismissed, the notice period, personnel service years, age structure (pension costs), the size of the company, training needs, and relocation costs. Some of the personnel can be employed in the aftercare work.

Aftercare and monitoring costs The costs of aftercare and monitoring depend largely on how the water flowing from the site needs to be monitored, how the safety monitoring of the site has to be organized, and how dams need to be monitored. Permit requirements related to closure often require samples to be taken, laboratory tests to be conducted, results to be analysed, and reports to be written. The annual cost can be EUR 5,000 to 20,000 depending on the extent of the area and the permit requirements.

Using cost estimates in prioritizing alternatives The purpose of mine aftercare is to return the area to a state required by law. It is also important to do the job properly the first time so as to avoid costly rework. Comparing the costs of various options with their benefits, and assessing the consequences of each environmental risk and the costs of reducing that risk through risk assessment, result in an identification of the best options. Risk assessment also helps analyse any overlapping effects of planned actions. Communications on the cost estimate and actual costs are of great importance in maintaining relations with the community.

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9. DEFINITIONS

Acid Mine Drainage (AMD), Acid Rock Drainage (ARD) Acidic Drainage stemming from open pit, underground mining operations, waste-rock or tailings facilities that contain free sulphuric acid and dissolved metals sulphate salts, resulting from the oxidation of contained sulphide minerals or additives to the process. The acid dissolves minerals in the rocks, further changing the quality of the drainage water. Acid Potential (AP) Maximum potential acid generation of the material. BAT Reference Document (=BREF –document) The EU member states’ competent authorities and industry co-operate on the development of BAT reference documents for each of the industries listed in Annex I of the IPPC Directive (96/61/EC). These documents describe the techniques, which it is agreed that can be defined as BAT, as well as the agreed indicative emission levels to be applied when such techniques are used. Best available techniques - BAT Best available technique refers to methods of production and treatment that are as efficient and advanced as possible and technologically and economically feasible, and to methods of designing, constructing, maintenance and operation with which the contaminative effect of activities can be prevented or most efficiently reduced; (Section 3, Environmental Protection Act). Concentrate The valuable minerals/marketable products extracted from the ore in mineral processing. EIA -procedure Procedure for environmental impacts assessment based on Act on Environmental Impact Assessment Procedure (468/1994). Gangue The part of an ore that is not economically desirable but cannot be avoided in excavation. General plan for mine operations Based on Decision of Ministry of Trade and Industry (921/1975) a general plan has to be delivered to Safety Technology Authority of Finland prior to commencement of mining operations. General plan should cover aspects related to organizing and commencement of excavations; describe locations of activities at mine site, and present a schedule for mine construction (Sections 2 to 4, Decision 921/1975).

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Hazardous waste Waste materials listed as hazardous waste in the annex of the Ministry of the Environment Decree on the list of the most common wastes and of hazardous wastes (1129/2001) Industrial minerals Geological materials, which are mined for their commercial value, which are not fuel (fuel minerals or mineral fuels) or gemstones and are not sources of metals (metallic minerals). They are used in their natural state or after beneficiation either as raw materials or as additives in a wide range of applications. Inert waste Waste that does not undergo any significant physical, chemical or biological transformations. Inert waste will not dissolve, burn or otherwise physically or chemically react, biodegrade or adversely affect other matter with which it comes into contact in a way likely to give rise to environmental pollution or harm human health. The total leachability and pollutant content of the waste and the ecotoxicity of the leachate must be insignificant, and in particular not endanger the quality of surface water and/or groundwater. (1999/31/EC) Landfill Waste disposal site for the deposit of the waste onto or into land (i.e. underground), including: - internal waste disposal sites (i.e. landfill where a producer of waste is carrying out its own waste disposal at the place of production), and - a permanent site (i.e. more than one year) which is used for temporary storage of waste, but excluding: - facilities where waste is unloaded in order to permit its preparation for further transport for recovery, treatment or disposal elsewhere, and - storage of waste prior to recovery or treatment for a period less than three years as a general rule, or - storage of waste prior to disposal for a period less than one year (1999/31/EC). Each landfill is classified in one of the following classes: - landfill for hazardous waste, - landfill for non-hazardous waste, - landfill for inert waste (1999/31/EC). Metallic ores, metalliferous ores Metal-bearing; pertaining to a mineral deposit from which a metal or metals can be extracted by enrichment or metallurgical processes.


Mine Facility that produces exploitable minerals through excavating the earth crust and by extracting the valuable minerals from unexploitable rock. Mine closure Permanent cessation of mining operations and all subsequent activity related to decommissioning and site rehabilitation or ongoing monitoring. Mineral processing, mineral dressing Mechanical, physical and/or chemical processes applied to produce marketable mineral products (concentrates) from ore. Neutralization potential (NP) Material’s capacity to neutralize acidity. Natural stones Term “natural stones” refers to rocks that have been formed through geological processes and have economic value. According to Natural stone Handbook (Kiviteollisuusliitto ry 1994, in Finnish) Finnish Natural stones are classified into four main categories: 1) igneous rocks, 2) schists and quartzites, 3) marbles, as well as 4) soapstones and serpentinites. Natural stones are commonly used as architectural rocks, in environmental planning and in interior decoration.(Aatos 2003). Non-hazardous waste Waste not regarded as hazardous waste (1999/31/EC). Ore Naturally occurring material from which a mineral or minerals of economic value can be extracted at a reasonable profit. Overburden Unconsolidated earth material on top of the orebody. In case of open pit mining operations, it is removed prior to extraction of the ore and deposited at the mine site. In Finland, term overburden is mainly used for soil materials.


Plan for the exploitation of the concession and auxiliary area A plan for the exploitation of the concession and auxiliary area included in the concession application defined in the Mine Act (503/1965). Plan should include a report on the factors that determine the extent and shape of the concession area, including a description of the locations of overburden, waste rock and tailings facilities in the concession or auxiliary area. Rehabilitation, reclamation Activities taken to restore the mine site into condition that poses no hazard to human health or environment after the ore is extracted. Rock material of secondary quality Residue rock formed in soapstone production composed of poor quality soapstone invalid for production. Stakeholder A person, group or organization with the potential to be affected by the process of, or outcome of, mine closure. Tailings Those portions of washed or milled ore that are regarded as too poor to be treated further, as distinguished from the concentrate, or material of value. Tailings consist mainly of gangue and may include process water, process chemicals and portions of the unrecovered minerals. Tailings area, tailings pond, tailings impoundment Engineered structure designed for managing tailings and for clearing and recycling the process water. Waste rock, barren rock, surplus stone Part of the orebody, without or with low grades of ore, which cannot be mined and processed profitably, but is needed to remove to exploit the ore. Waste rock is commonly either deposited in stockpiles at the mine site or utilized as backfilling in mining or in earth construction at or outside the mine site.

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10. SOURCE MATERIAL 10.1 Statutes and regulations Reference: FINLEX Data Bank – Electronic Statutes of Finland (www.finlex.fi); EUR-Lex – Electronic Data Bank of European Union Law (http://eur-lex.europa.eu/) 2003/33/EC: Council Decision of 19 December 2002 establishing criteria and procedures for the acceptance of waste at landfills pursuant to Article 16 of and Annex II to Directive 1999/31/EC Accounting Act (1336/1997) Act on Compen sat ion for Env i ron ment al Da mage (737/1994) Act on Environmental Impact Assessment Procedure (468/1994) (in Finnish) Act on Implementation of the Legislation on Environmental Protection (113/2000) Act on the Protection of Buildings (60/1985) Act on the Safe Handling of dangerous Chemicals and Explosives (390/2005) (in Finnish) Act on Water Resources Management (1299/2004) (in Finnish) Antiquities Act (295/1963) (in Finnish) Chemicals Act (744/1989) (in Finnish) Code of Real Estate (540/1995) Council Directive 1999/31/EC of 26 April 1999 on the landfill of waste. Council of State Decision on the protection of groundwater against pollution caused by certain substances dangerous for health and the environment (364/1994) (in Finnish) Dam Safety Act (413/1984) (in Finnish) Dam Safety Decree (574/1984) (in Finnish) Decision of the Ministry of Trade and Industry on safety regulations in mining (921/1975) (in Finnish) Decision of the Ministry of Trade and Industry on mine maps (1218/1995) (in Finnish) Decree on the Industrial Handling and Storage of Dangerous Chemicals (59/1999) (in Finnish) Decree on Environmental Impact Assessment Procedure (713/2006) (in Finnish) Directive 2004/35/EC of the European Parliament and of the Council of 21 April 2004 on environmental liability with regard to the prevention and remedying of environmental damage Directive 2006/21/EC of the European Parliament and of the Council of 15 March 2006 on the management of waste from extractive industries and amending Directive 2004/35/EC - Statement by the European Parliament, the Council and the Commission.

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Directive 2006/12/EC of the European Parliament and of the Council of 5 April 2006 on waste Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy Environmental Damage Insurance Act (81/1998) Environmental Protection Act (86/2000) Environmental Protection Decree (169/2000) Forest Act (1093/1996) Government Decision on approval of Finland’s proposal for the European Union’s Natura 2000 network 20.8.1998 Government Decision on landfills (861/1997); Government Decision (1049/1999) on an amendment to the Government decision on landfill sites (in Finnish) Government Decision on the discharge into the aquatic environment of certain substances posing a hazard to the environment and to health (363/1994) (in Finnish) Government Decision to supplement Finland’s proposal for the European Union’s Natura 2000 network 25.3.1999 Government Decision to supplement Finland’s proposal for the European Union’s Natura 2000 network 8.5.2002 Government Decision 22.1.2004 on sites returned by the Supreme Administrative Court for reconsideration of Finland’s proposal for Natura 2000 network Government Decree (889/2006) on an amendment of the Environmental Protection Decree (in Finnish) Government Decree on the discharge into the aquatic environment of certain substances posing a hazard to the environment and to health (1022/2006) Government Decree on the assessment of soil contamination and need for remediation (214/2007) (in Finnish) Government Proposal (84/1999) to Parliament on reform of environmental protection and water legislation. (in Finnish) Health Protection Act (763/1994) (in Finnish) Land Extraction Act (555/1981) Land Use and Building Act (132/1999) Mining Act (503/1965) (in Finnish) Nature Conservation Act (1096/1996) Nature Conservation Decree (160/1997) Penal Code (39/1889) Radiation Act (230/1989) (in Finnish) Tort Liability Act (412/1974) Waste Decree (1390/1993) Waste Management Act (673/1978) Waste Act (1072/1993) Water Act (264/1961)


10.2 References Aatos, S. (toim.) 2003. Luonnonkivituotannon elinkaaren aikaiset ympäristövaikutukset. Suomen ympäristö 656. 188 s. Ahonen, M. 1997. Rikastushiekkojen materiaaliominaisuudet. MINPRO. Rikastushiekan läjitystekniikat. Väliraportti. Oulun yliopisto. Geotekniikan laboratorio. Oulu, joulukuu 1997. 32 s. + liitt.

DME 2002. Aide memoire for the preparation of environmental management programme reports for prospecting and mining. Department of Minerals and Energy. Republic of South-Africa. http://www.dme.gov.za/minerals/ aide_memoire.htm

Alanko, K. & Järvinen, K. 2001. Pilaantuneen maa-alueen kunnostuksen yleissuunnitelma. Ympäristöopas 83, Suomen ympäristökeskus. 77 s.

Dold, B. 2001. A 7-step sequential extraction for geochemical studies of copper sulfide mine waste. In Securing the Future, International Conference on Mining and the Environment, Proceedings. June 25-July 1, 2001, Skellefteå, Sweden, pp. 158-170.

Alapassi, M., Rintala, J. & Sipilä, P. 2001. Maa-ainesten ottaminen ja ottamisalueiden jälkihoito. Ympäristöministeriö, alueiden käytön osasto. Ympäristöopas 85. 101 s.

DTLR 2001. Multi-Criteria Analysis: A Manual. London, Department for Transport, Local Government and the Regions. http://www.dtlr.gov.uk/about/multicriteria.

Backman, B., Lahermo, P., Väisänen, U., Paukola, T., Juntunen, R., Karhu, J., Pullinen, A., Rainio, H. & Tanskanen, H. 1999. Geologian ja ihmisen toiminnan vaikutus pohjaveteen. Seurantatutkimuksen tulokset vuosilta 1969-1996. Geologian tutkimuskeskus, tutkimusraportti 147. 261 s.

EC 2004. Reference Document on Best Available Techniques for Management of Tailings and Waste Rock in Mining Activities. July 2004. European Commission, DirectorateGeneral JRC Joint Research Centre, Institute for Prospective Technological Studies, Technologies for Sustainable Development, European IPPC Bureau. 511 s.

Baker B.J. & Banfield J.F. 2003. Microbial communities in acid mine drainage. FEMS Microbiology Ecology 44, pp. 139-152. Beamish, D. & Kurimo, M. 2000. Trial airborne surveys to assess minewater pollution in the UK. Extended Abstracts, 62nd EAGE Conference and Technical Exhibition, Glasgow, 29 May-2 June 2000. Britschgi, R. & Gustafsson, J. (toim.) 1996. Suomen luokitellut pohjavesialueet. Suomen ympäristökeskus. Suomen ympäristö 55. 384 s. Brodie, M.J., Robertson, A.M. & Gadsby, J.W. 1992. Cost effective closure plan management for metal mines. http:// www.robertsongeoconsultants.com/papers/metal_mines. pdf. Carlson, L., Hänninen, P. & Vanhala, H. 2002. Ylöjärven Paroistenjärven kaivosalueen nykytilan selvitys. Geologian tutkimuskeskus, raportti S/41/0000/3/2002. 54 s. Chevrel, S., Kuosmanen, V., Grösel, K., Marshiv, S., Tukiainen, T., Schäffer, U., Quentalvii, L., Vosenv, P., Loudjan, P., Kuronen, E. & Aastrup, P. 2003. Remote-sensing monitoring of environmental impacts. Mining Environmental Management 11(6), 19-23. Couillard, Y., Courcelles, M., Cattaneo, A. & Wunsam S. 2004. A test of the integrity of metal records in sediment cores based on the documented history of metal contamination in Lac Dufault (Québec, Canada). Journal of Paleolimnology 32: 149-162. DETR 2000. Environment Agency and Institute for Environment and Health Guidelines for Environmental Risk Assessment and Management, Revised Department Guidance. DETR, London. 88 s. Dickinson, N., Mackay, J., Goodman, A. & Putwain, P. 2000. Planting trees on contaminated soils: Issues and guidelines. Land Contamination and Reclamation 8 (2), 87 – 101.


EIPPC 2003. Integrated Pollution Prevention and Control. Reference Document on the General Principles of Monitoring. European Commission. 123 s. EIPPC 2004. Integrated Pollution Prevention and Control. Draft Reference Document on Economics and CrossMedia Effects. Draft November 2004. European Commission 170 s. Elo, S. & Vanhala, H. 2001. Geofysiikan uudet ympäristösovellukset. Teoksessa: Idman, H. & Rönkä, E. (toim.): Kestävä kehitys – tutkimuksen haasteet ja mahdollisuudet. GTK – SYKE tutkimusseminaari 12.09.2001. Geologian tutkimuskeskus, Tutkimusraportti 153. ss. 86-94. Environment Australia 2002. Mine Decommissioning. Booklet in a series on Best Practice Environmental Management in Mining. Commonwealth of Australia. ISBN 0 642 48797 9 of the series 0 642 19418 1. http://www.deh.gov.au/ settlements/industry/minerals/booklets/mine/index.html EPA 2000. Introduction to Phy toremediation. EPA / 600/R-99/107. U.S. Environmental Protection Agency, National Risk Management Research Laboratory. 72 s. + liitt. Ericsson, M. & Noras, P. 2005. A Note on Minerals-based Sustainable Development: One Viable Alternative. Minerals & Energy vol. 20 (1), pp. 29-39. Euromines 2005. The ultimate SME implementation guide for ISO 9001:2000, ISO 14001:2004 management systems. Section 1, General, Version 2005. 26 s. http://www. euromines.org/publications_downloads/general.pdf. 4.10.2005. Fortin, D., Davis, B., Southam, G. & Beveridge, T.J. 1995. Biogeochemical phenomena induced by bacteria within sulfide mine tailings. Journal of Industrial Microbiology 14, pp. 178-185.

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Gaál, G., Hänninen, P., Lahti, M., Schmidt-Thomé, P., Sulkanen, K., Vanhala, H., Buckup, K., Sideris, G., Zervos, F., Stoll, R., Viehweg, M. & de Boom, H. 2001. AERA. Assessment of Environmental risks by airborne geophysical techniques validated by geophysical field measurements. Ed. M. Lahti. Final report. ENV4-CT98-0793. Geologian tutkimuskeskus, arkistoraportti Q 20/2001/1. 204 s. Gazea, B., Adam, K. & Kontopoulos, A. 1996. A review of passive systems for the treatment of acid mine drainage. Minerals Engineering. Vol. 9, No 1, pp. 23-42.

Juvankoski, M. & Tolla, P. 2004. Kaivospatojen ja -kasojen stabiliteettitarkastelut, VTT, Työraportti 6.11.2004. Kaartinen, T. & Wahlström, M. 2005. Hituran kaivoksen sivukivien ja rikastushiekan staattiset kokeet ja liukoisuuskokeet. Työraportti, VTT Prosessit 19.5.2005. 32 s. Karjalainen, M. 2003. Kaivostoiminnasta poistettavien sulfidimalmialueiden kasvillistaminen. Jyväskylän yliopisto, Bio- ja ympäristötieteiden laitos, Pro gradu -tutkielma 20.10.2003. 91 s.

GTK 2007. Metals and Minerals Production in Finland 2006. http://www.gtk.fi/luonnonvarat/tuotanto/ teollisuusmineraalit.html, accessed 15.11.2007

Kauppila, T. 2006. Sediment-based study of the effects of decreasing mine water pollution on a heavily modified, nutrient enriched lake. Journal of Paleolimnology 35 (1), 25-37.

Haavisto, M. (ed.) 1983. Maaperäkartan käyttöopas 1:20 000, 1:50 000. Resumeé = Summary: Grundkartläggningen av Finlands jordarter = Basic mapping of Quaternary deposits in Finland. Geologinen tutkimuslaitos. Opas 10. 74 s.

Kauppila, J. & Kosola, M.-L. 2005. Jätealan ympäristöluvat ja taloudellinen vakuus. Ympäristöopas 119. 60 s. http:// www.ymparisto.fi/default.asp?contentid=125506&lan=fi. 22.7.2005.

Hall, G.E.M., Vaive, J.E, Beer, R. & Hoashi, M. 1996. Selective leaches revisited, with emphasis on the amorphous Fe oxyhydroxide phase extraction. Journal of Geochemical Exploration 56, 59-78.

Kiviteollisuusliitto ry 1994. Luonnonkivikäsikirja. Kleinmann, R.L.P., Crerar, D.A. & Pacelli, R.R. 1981. Biogeochemistry of acid mine drainage and a method to control acid formation. Mining Engineering, Vol. 33, No.3, pp. 300-305.

Hänninen, P. 1991. Maatutkaluotaus maaperägeologisissa tutkimuksissa. Summary: Ground penetrating radar in Quaternary geological studies. Geologian tutkimuskeskus. Tutkimusraportti 103. 35 p. Hatakka, T. & Heikkinen, P. 2005. Pinta- ja pohjavesiseurannan järjestäminen kaivoksen sulkemisen jälkeen. Geologian tutkimuskeskus, julkaisematon raportti 30.9.2005. 14 s. Heikkinen, P. 2005. Hituran kaivoksen rikastushiekan mineraloginen ja kemiallinen koostumus. Geologian tutkimuskeskus. Julkaisematon tutkimusraportti 7.7.2005. 19 s. Heikkinen, P.M., Korkka-Niemi, K., Lahti, M. & Salonen, V.-P. 2002. Groundwater and surface water contamination in the area of the Hitura nickel mine, western Finland. Environmental Geology 42 (4), 313-329. Heikkinen, P., Pullinen, A. & Hatakka, T. 2004. Hituran kaivoksen sivukivikasojen ja rikastushiekka-alueen ympärysojien pintavesikartoitus, virtaamamittaukset sekä ympärysojien ja kaivoksen vesien laatu toukokuussa 2004. Geologian tutkimuskeskus. Julkaisematon tutkimusraportti 29.10.2004. Heikkinen, P.M., Korkka-Niemi, K. & Salonen, V.-P. 2005. Kaivostoiminnan pinta- ja pohjavesivaikutuksien ilmentyminen – happamat ja neutraalit kaivosvedet. Teoksessa: Tuhkanen, S. (toim.): Geologian tutkijapäivät 14.-15.3.2005 Turku. Ohjelma-tiivistelmät – osallistujat. ss. 48-49. Himmi, M. & Sutinen, H. 2005. Best available technique (BAT). Paras käytettävissä oleva tekniikka. Asiakirjan sanasto. Englanti-suomi. Yleiset termit, lyhenteet ja aineet. 39 s. Juslén, J. 1995. Sosiaalisten vaikutusten arviointi (SVA); Monipuolisempaan suunnitteluun. STAKES, raportteja 180. 121 s.

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Korkka-Niemi, K. 2001. Cumulative geological, regional and site-specific factors affecting groundwater quality in domestic wells in Finland. Monographs of the Boreal Environment Research 20. 98 s. Koskensyrjä, M. 2003. Ympäristöriskien analysointi. http:// turva.me.tut.fi/kurssit/3105010/02-03/koskensyrja2003. pdf, accessed 9.7.2004. KTM 2003a. Esitys kaivoslain uudistamiseksi. Kaivoslain muutostarpeita selvittävä työryhmä. Kauppa- ja teollisuusministeriön työryhmä- ja toimikuntaraportteja 2/2003. 135 s. KTM 2003b. Kaivosturvallisuussäädösten muutostarpeita selvittävän työryhmän raportti. KTM:n työryhmä- ja toimikuntaraportteja 3/2003. Helsinki: Edita Publishing Oy. 132 s. KTM/GTK 2005. Metals and mineral production. http://www. gsf.fi/explor/eco_minprod_frame.htm Kumpulainen, S. 2004. Hituran kaivoksen sivukivikasojen pitkäaikaiskäyttäytymisen mallintaminen. Osa 1. Pitkäaikaiskäyttäytymisen arvioinnissa käytettävät menetelmät. Kirjallisuusselvitys. Geologian tutkimuskeskus, julkaisematon tutkimusraportti. Espoo 27.9.2004. Kumpulainen, S. 2005a. Hituran kaivoksen avolouhoksen vedenlaadun mallintaminen. Osa 2. Veden laadun mallintaminen. Geologian tutkimuskeskus, julkaisematon tutkimusraportti. Espoo 7.5.2005. 25 s. Kumpulainen, S. 2005b. Hituran kaivoksen sivukivikasojen pitkäaikaiskäyttäytymisen mallintaminen. Osa 2. Mallintaminen. Geologian tutkimuskeskus. Julkaisematon tutkimusraportti 3.7.2005. 31 s.


Kumpulainen, S. & Heikkinen, P. 2004. Tekes – kaivostoiminnan ympäristötekniikka. Hituran kaivoksen sivukivikasojen kemiallisen ja mineralogisen koostumuksen vaihtelu. Geologian tutkimuskeskus, 8.7.2004. 16 s. Kuosmanen, V., Arkimaa, H., Helminen, T., Hyvönen, E., Kuronen, E., Laitinen, J., Lerssi, J., Middleton, M., Ruohomäki, T., Räisänen, M.-L., Saarelainen, J. & Sutinen, R. 2004. MINEO Boreal environment test site, Finland. Contamination/impact mapping and modeling – Final Report. 85 s., 6 liites. Geologian tutkimuskeskus, arkistoraportti, RS/2004/2. Kuosmanen, V.V., Arkimaa, H.A., Kuosmanen, E.L. & Laitinen, J.L. 2003. Combined use of AISA, HyMap and ultraspectral image data for detection of environmental features, a case history from Elijärvi chromium mine, Finland. In: Benes (ed.): Geoinformation for European-wide Integration. Millpress, Rotterdam. ISBN 90-77017-71-2. ss. 473-478. Lahermo, P., Ilmasti, M., Juntunen, R., & Taka, M. 1990. Suomen geokemian atlas, osa 1. Suomen pohjavesien hydrogeokemiallinen kartoitus. Geologian tutkimuskeskus, Espoo. 66 s. Lahermo, P., Väänänen, P., Tarvainen, T., & Salminen, R. 1996. Suomen geokemian atlas, osa 3. Ympäristögeokemia – purovedet ja sedimentit. Geologian tutkimuskeskus, Espoo. 150 s. Lahermo, P., Tarvainen, T., Hatakka, T., Backman, B., Juntunen, R., Kortelainen, N., Lakomaa, T., Nikkarinen, M., Vesterbacka, P., Väisänen, U. & Suomela, P. 2002. Tuhat kaivoa – Suomen kaivovesien fysikaalis- kemiallinen laatu vuonna 1999. Geologian tutkimuskeskus, Espoo. Tutkimusraportti 155. 92 s. Ledin, M. & Pedersen, K. 1996. The environmental impacts of mine wastes – Roles of micro-organisms and their significance in treatment of mine wastes. Earth-Science Reviews 41, pp. 67-108. Leino, T., Suomela, P., Kosonen, M., Mroueh, U.-M., Nevalainen, J., & Mäkelä, E. 2005. Kaivoksen sulkemiseen liittyvä lainsäädäntö. Kaivostoiminnan ympäristötekniikka –projektin lakityöryhmän yhteenveto sulkemiseen liittyvästä lainsäädännöstä. Julkaisematon tutkimusraportti. 31.10.2005. Lonka, H., Hjelt, M., Vanhanen, J., Raivio, T. (Gaia Group), Vaahtoranta, T., Visuri, P., Väyrynen, M. (Ulkopoliittinen instituutti), Frinking, E., O’Brien, K. (Rand Europe) 2002. Riskien hallinta Suomessa; Esiselvitys. Helsinki: Sitra, Sitran raportteja. http://www.sitra.fi/Julkaisut/raportti23. pdf. 144 s. Maa- ja metsätalousministeriö. 1997. Patoturvallisuusohjeet. Helsinki. Maa- ja metsätalousministeriön julkaisuja 7/1997. 78 s.


Mäkelä, A., Antikainen, S., Mäkinen, I., Kivinen, J. & Leppänen, T. 1992. Vesitutkimusten näytteenottomenetelmät. Vesi- ja ympäristöhallinnon julkaisuja – sarja B, nro. 10. Helsinki: Vesi- ja ympäristöhallitus, VAPK-kustannus. 87 s. MEND 1994. Acid Mine Drainage-Status of Chemical Treatment and Sludge Management Practices. Mine Environment Neutral Drainage Program. MEND Report 3.32.1. June 1994. 62 p. MEND 1996. Review of passive systems for treatment of acid mine drainage. Mine Environment Neutral Drainage Program. MEND Report 3.14.1. May 1996. 72 p. Mining Association of Canada 1998. A Guide to the Management of Tailings Facilities. 54 s. MMSD 2002a. Mining for the Future. Appendix B: Mine Closure Working Paper. Mining, Minerals and Sustainable Development, Report No. 34, International Institute for Environment and Development / World Business Council for Sustainable Development. 22 s. MMSD 2002b. Seven Questions to Sustainability. How to assess the contribution of mining and minerals activities. Task2 WG, MMSD North America. IISD, MMSD, WMCSD. 66 s. Mroueh, U.-M., Vahanne, P., Eskola, P., Pasanen, A., Wahlström, M., Mäkelä, E. & Laaksonen, R. 2004. Pilaantuneiden maiden kunnostushankkeiden hallinta. VTT Tiedotteita 2245, Yleinen Teollisuusliitto, Ympäristöyritysten liitto ry, VTT. 317 s. + liitteet 44 s. Myös: http://www.vtt.fi/inf/ pdf/tiedotteet/2004/T2245.pdf Mroueh, U.-M., Heikkinen, P., Jarva, J., Voutilainen, P., Vahanne, P. & Pulkkinen, K. 2005a. Riskinarviointi kaivosten sulkemishankkeessa, 28.10.2005. VTT Prosessit. Projektiraportti PRO3/P3039/05. Mroueh, U.-M., Mäkelä, E. & Vestola, E. 2005b. Paras käyttökelpoinen tekniikka kaivosten rikastushiekka- ja sivukivialueiden sulkemisessa. VTT, luottamuksellinen projektiraportti PRO3/P51/04. 14.10.2005. 25 s. Muller, D.B. & Graedel, T.E. 2003. Model Development for the Global Cycles of Iron and Its Alloying and Coating Elements, Workshop Report, Yale University, 6-8 February 2003. Mustikkamäki, U.-P. 2000. Metallipitoisten vesien biologisesta käsittelystä Outokummun kaivoksilla. Vuoriteollisuus 1, ss. 44-47. Naturvårdsverket 2002. Uppföljning av efterhandlingsprojekt inom gruvsektorn – Åtgärder, kostnader och resultat. Rapport 5190 Maj 2002. Noras, P. 2005a. Sulkemisen omaehtoinen normitus. Geologian tutkimuskeskus, julkaisematon tutkimusraportti. Noras, P. 2005b. Sulkeminen ja kestävän kehityksen vaatimukset. Geologian tutkimuskeskus, julkaisematon tutkimusraportti.

125

Paktunc, A.D. 1998. MODAN: an interactive computer program for estimating mineral quantities based on bulk composition. Computers and Geosciences 24 (5), 425-431. Paukola, T., Pullinen, A., Juntunen, R., Backman, B. & Tarvainen, T. 1999. 1000 kaivoa – näytteenotto-ohjeet. Arkistoraportti P32.4.009. Geologian tutkimuskeskus. 10 s. Penttinen, S. 2000. Electrical and hydraulic classification of forest till soils in central Lapland, Finland. Geological Survey of Finland. Bulletin 398. 88 p. PIRAMID Consortium 2003. Engineering guidelines for the passive remediation of acidic and/or metalliferous mine drainage and similar wastewaters. European Commission 5th Framework RTD Project no. EVK1-CT-1999-000021 “Passive in-situ remediation of acidic mine / industrial drainage” (PIRAMID). University of Newcastle Upon Tyne, Newcastle Upon Tyne UK. 166pp. http://www. piramid.org/PIRAMID%20Guidelines%20v1.0.pdf Price, W.A. 1997. DRAFT Guidelines and recommended methods for the prediction of metal leaching and acid rock drainage at minesites in British Columbia. B.C. Ministry of Employment and Investment. 141 p. Puustinen, K. 2003. Suomen kaivosteollisuus ja mineraalisten raaka-aineiden tuotanto vuosina 1530-2001, historiallinen katsaus erityisesti tuotantolukujen valossa. Geologian tutkimuskeskus, arkistoraportti, M 10.1/2003/3. 578 s. Rae, J.E. & Parker, A. 1996. Techniques for validating the historic record of lake sediments. A demonstration of their use in the English Lake District. Applied Geochemistry 11, 211-215. Räisänen, M.L., Niemelä, K. & Saarelainen, J. 2003. Rautasulfidipitoisen rikastushiekan läjitysalueen rakenne ja ympäristön vesien nykytila. Vuosien 2000 ja 2001 seurantatulokset, Hammaslahden vanha kuparikaivos. Geologian tutkimuskeskus, Kuopion yksikkö, raportti S/44/0000/1/2003. 27 s. Räisänen, M.L., Vanhala, H. & Hänninen, P 2000. Ympäristötutkimuksissa käytetyt menetelmät. Teoksessa: Carlson, L., Kuula-Väisänen, P. & Loukola-Ruskeeniemi, K. (toim.): Ympäristö, terveys ja turvallisuus kaivannaisteollisuudessa. Seminaari 31.10.-1.11.2000 Haikon kartanossa. Vuorimiesyhdistys – Bergsmannföreningen r.y. sarja B, nro 76, 68-70. Raw Materials Group 2002. Socio-Economic Impacts of the Finnish Extractive Industries. Reports for KTY. 89 s. http:// www.teknologiateollisuus.fi/files/876_report.pdf Raw Materials Group 2005. Raw materials data. http://www. rmg.se/RMG2005/pages/database.htm Robertson, A. & Shaw, S. Mine Closure – Closure Criteria and Indicators. Robertson GeoConsultants Inc. http:// technology.infomine.com/enviromine/issues/cls_criteria. html. accessed 15.11.2004.

126

Robertson, J.D., Tremblay, G.A. & Fraser, W.W. 1997. Subaqueous tailings disposal: A sound solution for reactive tailings. Fourth International Conference on Acid Rock Drainage: Vancouver, B.C. Canada, May 31-June 6 1997: Proceedings, Vol. 3. pp. 1029-1041. Saarela, J. 1990. Kaivopatojen geoteknisistä ominaisuuksista ja ympäristövaikutuksista. Vesi- ja ympäristöhallinnon julkaisuja. Sarja A 64. Vesi- ja ympäristöhallitus. Helsinki 1990. 148 s. Salminen, R., Heikkinen, P., Nikkarinen, M., Parkkinen, J., Sipilä, P., Suomela, P. & Wennerström, M. 1999. Ympäristövaikutusten arviointimenettelyn opas kaivoshankkeisiin. Kauppa- ja teollisuusministeriön tutkimuksia ja raportteja 20/1999, Teknologiaosasto. 80 s. Salminen, R., Chekushin, V., Tenhola, M., Bogatyrev, I., Glavatskikh, S.P., Fedotova, E., Gregorauskiene, V., Kashulina, G., Niskavaara, H., Polischuok, A., Rissanen, K., Selenok, L., Tomilina, O., & Zhdanova, L. 2004. Geochemical Atlas of Eastern Barents Region. Journal of Geochemical Exploration, vol. 83 (1-3). 530 s. Salonen, V.-P., Artimo, A., Heikkinen, P.M., Korkka-Niemi, K., Pietilä, S., Nuutilainen, O. & Pulkkinen, K. 2001. Hituran kaivoksen rikastushiekka-alueen jätevesivaikutuksen torjunta Töllinperän pohjavesialueella. Teoksessa: Salonen, V.-P. & Korkka-Niemi, K.: Kirjoituksia pohjavedestä. 3. ympäristögeologian päivät, Turku 13.-14.3.2000. Turun yliopisto, Geologian laitos. Vammalan kirjapaino. ss. 251-263. Salonen, V.-P., Tuovinen, N. & Valpola, S. 2006. History of mine drainage impact on Lake Orijärvi algal communities, SW Finland. Accepted to Journal of Paleolimnology (Vol. 35:2). 15 pp. Siiro, P. & Kohonen, T. 2003. Selvitys rannikkosedimenttien haitta-ainepitoisuuksien normalisointimenetelmistä. Suomen ympäristökeskuksen moniste 274, 29 s. Smol, J.P. 2002. Pollution of lakes and rivers. A paleoenvironmental perspective. Arnold, London. 280 s. Sosiaali- ja terveysministeriö 1998. Sosiaali- ja terveysministeriön ohjeet ympäristövaikutusten arvioinnista annetun lain (468/94) soveltamisesta; Terveysvaikutusten arviointi ja sosiaalisten vaikutusten arviointi. Soveri, J., Mäkinen, R. & Peltonen, K. 2001. Pohjaveden korkeuden ja laadun vaihteluista Suomessa 1975-1999. Suomen ympäristökeskus. Suomen ympäristö 420. 382 s. SGY 2002. Suomen geoteknillinen yhdistys ry. Ympäristögeotekninen näytteenotto-opas: maa-, huokoskaasu- ja pohjavesinäytteet, moniste. 37 s. + 7 liitettä. Suomen Rakennusinsinöörien Liitto RIL r.y. 1989a. Pohjarakennusohjeet RIL-121-1988. Helsinki. Suomen Rakennusinsinöörien Liitto RIL r.y. Suomen Rakennusinsinöörien Liitto RIL r.y. 1989b. Rakennuskaivanto-ohje RIL-181-1989. Helsinki. Suomen Rakennusinsinöörien Liitto RIL r.y. 120 s.


Suomen Vesiyhdistys, 2005. Pohjavesitutkimusopas – Käytännön ohjeita. Suomen vesiyhdistys r.y. Vammala. 194 s. SYKE 2002. Suomen ympäristökeskuksen ehdotus kansallisiksi haitallisiksi aineiksi (13.6.2003) sekä kyseisten aineiden laatunormeiksi (26.3.2004). SYKE-P-281-040. Tenhola, M., Lahermo, P., Väänänen, P. & Lehto, O. 2004. Alueellisessa geokemiallisessa purovesikartoituksessa todettujen fysikaalisten ominaisuuksien ja alkuainepitoisuuksien vertailu Suomessa vuosina 1990, 1995 ja 2000. Geologian tutkimuskeskus, Espoo. Tutkimusraportti 159. 35 s. Tiehallinto 1994. Penger ja kerrosrakenteet. Tierakennustöiden yleiset laatuvaatimukset ja työselitykset. Tielaitos, Helsinki. TIEL 2212460-94. 65 s. Tiehallinto 1999. Murskaustyöt. Tienrakennustöiden yleiset laatuvaatimukset ja työselitykset. Tielaitos, Helsinki. TIEL 2212809-98. 30 s. Tiehallinto 2000. Tienrakennustöiden yleiset laatuvaatimukset ja työselitykset TYLT: Yleiset perusteet – Leikkaukset, kaivannot ja avo-ojarakenteet – Penger- ja kerrosrakenteet. – Lisäykset ja muutokset vuonna 2000, TIEL 2210014-2000. Helsinki. Tiehallinto. 60 s. Tuomainen, J. 2001. Vastuu saastuneesta ympäristöstä. WSOY, lakitieto. Helsinki. 513 s. United Nations/UNEP 1994. Environmental Management of Mine sites, Training Manual. Technical Report No. 30. 339 s.

Vanhala, H., Räisänen, M.L., Huotari, T., Valjus, T., Lehtimäki, J., & Suppala, I. 2004. Characterizing tailings impoundment at the closed Hammaslahti Cu-Zn mine, Finland. Teoksessa: Near surface 2004: 10 th European meeting of Environmental and Engineering Geophysics, Utrecht, The Netherlands, 6-9 September 2004: extended abstracts book. European Association of Geoscientists & Engineers. Abstract B035. Vanhala, H., Räisänen, M.L., Suppala, I., Huotari, T., Valjus, T. & Lehtimäki, J. 2005. Geophysical characterizing of tailings impoundment – a case from the closed Hammaslahti Cu-Zn mine, Eastern Finland. Teoksessa: Autio, S. (toim.): Geological Survey of Finland, Current Research 2003-2004. Geological Survey of Finland, Special Paper 38. ss. 49-61. Vespa 2005. Vesiympäristölle vaaralliset ja haitalliset aineet pintavesissä. Vesiensuojeludirektiivin tarkoittamien haitallisten aineiden ja prioriteettiaineiden toimeenpanoa valmistelevan työryhmän mietintö 8.6.2005. http://www. ymparisto.fi/download.asp?contentid=36580&lan=FI. 20.7.2005. VTT 2003. Riskianalyysin menetelmät. VTT Tuotteet ja Tuotanto. http://riskianalyysit.vtt.fi. Waybrant, K.R., Blowes, D.W. & Ptacek, C.J. 1998. Selection of reactive mixtures for use in permeable reactive walls for treatment of mine drainage. Environmental Science & Technology 32, pp. 1972-1979.

UNEP/WHO 1998. Mine Rehabilitation for Environment and Health Protection – a trainers manual. 430 s. Valjus, T., Breilin, O., Vanhala, H., Lehtimäki, J. 2004. Detailed geophysical study of glaciofluvial aquifer at Kempele, western Finland. In: Near surface 2004: 10th European Meeting of Environmental and Engineering Geophysics, Utrecht, The Netherlands, 6-9 September 2004: extended abstracts book. Houten: EAGE, 4 p.

Winterkorn, H. F. & Fang, H-Y. 1975. Foundation engineering handbook. Van Nostrand Reinhold Company Inc. 751 s. Ympäristöministeriö 2003a. Maankäyttö- ja rakennuslaki 2000. Osa: Opas 10. Maakuntamerkinnät ja -määräykset. Helsinki. Ympäristöministeriö. 100 s.

Valtion ympäristöhallinto 2004. Ympäristönäytteenottajien sertifiointi. http://www.ymparisto.fi/default. asp?contentid=5377&lan=fi. 15.9.2005.

Ympäristöministeriö 2004. Sedimenttien ruoppaus ja läjitysohje. Anvisning för muddring och deponering av muddringsmassor. Ympäristöopas 117, 121 s.

Vanhala, H. & Lahti, M. 2000. Sähköisten luotausten käyttö kaivosympäristötutkimuksissa – Tuloksia Hiturasta, Hammaslahdesta ja Otravaarasta. Teoksessa: Carlson, L., Kuula-Väisänen, P. & Loukola-Ruskeeniemi, K. (toim.): Ympäristö, terveys ja turvallisuus kaivannaisteollisuudessa. Seminaari 31.10.-1.11.2000 Haikon kartanossa. Vuorimiesyhdistys –Bergsmannföreningen r.y. sarja B, nro 76, 86-88.

Ziemkiewicz, P., Skousen, J., Brant, S., Sterner, P. & Lovett. R.J. 1997. Acid mine drainage treatment with armored limestone in open channels. Journal of Environmental Quality 26, 1017-1024.

Ympäristöministeriö 2003b. Maankäyttö- ja rakennuslaki 2000. Osa: Opas 11. Yleiskaavamerkinnät ja -määräykset. Helsinki. Ympäristöministeriö. 127 s.

10.3 Photographs Hitura mine: Photos 1, 2c, 12, 34, 38, 40, 41, 42 Päivi M. Heikkinen: Cover photo and photos 3a, 3b, 6, 9, 13, 16, 17 (larger), 23a, 23b, 27a, 27b, 28a, 28b, 35, 36, 39a, 43, 44, 48a, 48b, 50 Jaana Jarva: Photo 33


Tommi Kauppila: Photos 5, 15, 17 (smaller), 24, 25 Kirsti Korkka-Niemi: Photo 49 Ulla-Maija Mroueh: Photos 14, 47 Esa Mäkelä: Photo 46 Elina Vestola: Photos 2b, 37, 39b Geological Survey of Finland: 2a

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11. APPENDIXES APPENDIX 1. CHEMICAL AND PHYSICAL IMPACTS RELATED TO MINING AND MINERAL PROCESSING Table 1. Chemical impacts of different types of mining and mineral processing operations (Ashton et al. 2001) Operation Diamonds (m)

Chemical treatment?

Acid mine drainage

Alkalinity

Radioactivity

Arsenic

Mercury

Heavy metals

Cyanide

yes

no

no

occasionally

no

no

no

no

Diamonds (a)

no

no

no

occasionally

no

no

no

no

Gold/silver (m)

yes

yes

no

yes

occasionally

no

occasionally

yes

Gold (a)

yes

no

no

occasionally

no

yes

occasionally

no

PGE (m)

yes

yes

no

occasionally

no

no

yes

no

PGE (s)

yes

yes

no

occasionally

no

no

yes

no

Iron (m)

no

yes

no

no

no

no

yes

no

Iron (s)

no

yes

no

no

no

no

yes

no

Chromium (m)

no

no

yes

occasionally

no

no

yes

no

Chromium (s)

yes

yes

no

occasionally

no

no

yes

no

Wolfram (m)

no

no

no

yes

no

no

yes

no

Ni-Co (m)

yes

yes

no

occasionally

occasionally

no

yes

no

Ni-Co (s)

yes

yes

no

occasionally

occasionally

no

yes

no

Copper (m)

yes

yes

no

occasionally

no

no

yes

no

Copper (s)

yes

yes

no

occasionally

no

no

yes

no

Pb, Zn, Sb, Sn (m)

yes

yes

no

no

no

no

yes

no

Pb, Zn, Sb, Sn (s)

yes

yes (Zn)

no

no

no

no

yes

no

Building stone (q)

no

no

no

no

no

no

no

no

Coal (m,q)

no

yes

no

occasionally

no

no

no

no

Sulphur/pyrite

yes

yes

no

occasionally

no

no

yes

no

Manganese

no

no

occasionally

no

no

no

occasionally

no

Vanadium

yes

yes

no

no

no

no

yes

no

Phosphate*

yes

yes

no

occasionally

no

no

occasionally

no

Andalusite

no

no

no

no

no

no

no

no

Fluorspar

yes

no

occasionally

no

no

no

no

no

Other industrial minerals (q)

no

no

occasionally

occasionally

no

no

no

no

Vermiculite

yes

no

occasionally

occasionally

no

no

no

no

Chrysotile-asbestos

yes

no

occasionally

occasionally

no

no

occasionally

no

Gemstones (m,q)

no

no

no

no

no

no

no

no

As, Bi, Cd, Hg, Sb

yes

yes

no

occasionally

occasionally

occasionally

yes

no

occasionally

yes

no

occasionally

no

no

occasionally

no

Other metals

m = mine, a = alluvial, s = smelter, q = quarry PGE = platinum group elements * The most significant environmental impacts in phosphate quarrying are commonly related to exploitation of sedimentary deposits.

Reference Ashton, P.J., D. Love, H. Mahachi, P.H.G.M. Dirks 2001. An Overview of the Impact of Mining and Mineral Processing Operations on Water Resources and Water Quality in the Zambezi, Limpopo and Olifants Catchments in Southern Africa. Contract Report to the Mining, Minerals and Sustainable Development (SOUTHERN AFRICA) Project, by CSIREnvironmentek, Pretoria, South Africa and Geology Department, University of Zimbabwe, Harare, Zimbabwe. Report No. ENV-P-C 2001-042. xvi + 336 pp. http://www.iied.org/mmsd/mmsd_pdfs/SthAfrica_word_PPT/06_FinalReport.doc

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Table 2. Physical impacts of different types of mining and mineral processing operations (Ashton et al. 2001) Operation

Salinization

Siltation of water courses

Use of water

Area affected**

Large pits

Diversion of water courses

Impacts on vegetation

Diamonds (m)

possible

yes

medium

local

locally

locally

no

Diamonds (a)

possible

yes

medium

local

locally

yes

yes

Gold/silver (m)

possible

yes

large

local

locally

locally

no

Gold (a)

possible

yes

low

regional

locally

yes

yes

PGE (m)

possible

possible

medium

mine site

no

no

no

PGE (s)

possible

possible

low

local

no

no

no

Iron (m)

possible

possible

medium

local

yes

no

no

Iron (s)

no

no

medium

local

no

no

no

Chromium (m)

no

no

medium

mine site

locally

no

no

Chromium (s)

no

no

medium

local

no

no

no

Wolfram (m)

possible

possible

low

mine site

locally

locally

no

Ni-Co (m)

possible

possible

large

mine site

yes

locally

no

no

no

medium

local

no

no

no

Copper (m)

possible

possible

large

mine site

yes

locally

no

Copper (s)

no

no

medium

local

no

no

no

Pb, Zn, Sb, Sn (m)

possible

possible

large

mine site

locally

locally

no

Pb, Zn, Sb, Sn (s)

possible

possible

low

local

no

no

no

Building stone (q)

no

yes

low

local

yes

yes

yes

yes

possible

medium

local

yes

yes

no

possible

possible

medium

local

no

no

no yes

Ni-Co (s)

Coal (m,q) Sulphur/pyrite Manganese

no

yes

medium

mine site

yes

no

Vanadium

yes

yes

large

regional

locally

no

no

Phosphate*

yes

yes

large

regional

yes

no

no

Andalusite

no

yes

low

local

locally

no

locally

Fluorspar

yes

possible

low

local

locally

no

no

Other industrial minerals (q)

possible

possible

low

mine site

yes

locally

locally

Vermiculite

possible

yes

low

mine site

locally

no

locally

Chrysotile-asbestos

possible

yes

low

mine site

locally

no

no

Gemstones (m,q)

possible

possible

low

mine site

locally

locally

locally

As, Bi, Cd, Hg, Sb

no

possible

low

local

locally

locally

no

Other metals

no

possible

medium

mine site

locally

locally

no

m = mine, a = alluvial, s = smelter, q = quarry PGE = platinum group elements * The most significant environmental impacts in phosphate quarrying are commonly related to exploitation of sedimentary deposits. ** The area affected: mine site < local < regional

Chemical impacts relate mostly to waste rock and low-grade ore dumps, which are present at all sites, and to chemical treatment, with associated tailings dams, which are present at many mining sites. A wide variety of chemical impacts are possible and these can include acid mine drainage, the less common alkaline mine drainage, the release of highly toxic metals (most notably arsenic, antimony and mercury), the release of heavy metals, such as nickel, copper, cobalt, lead and zinc, and the release of cyanide from gold mining operations. Physical impacts on water resources include the use of water for a variety of mining operations, siltation of water courses by contribution to suspended solids loads, salinization by contribution to dissolved solids loads, the creation of large pits (that act as rain water traps), diversions of watercourses and sometimes associated extensive deforestation or devegetation of mine sites with concomitant erosion problems. The area affected can be segmented into three typical classes or groups, namely: the mine environs only (typically consisting only of the mine property), the local area (one or more properties that are adjacent to the mine property), or more widespread (regional).


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APPENDIX 2. QUESTIONS AND ISSUES TO CONSIDER WHEN EVALUATING THE CLOSURE PROCESS IN TERMS OF ECOLOGICALLY SUSTAINABLE DEVELOPMENT The 7 Questions Model (MMSD 2002b) applied for the mine closure process. 1. Engagement and commitment

“Is there an appropriate process for engaging all relevant stakeholders and communities, to ensure that the planning and implementation of the closure process complies with sustainable development principles? If such processes and commitments exist, how adequate and effective are they?” The focus here is on the effectiveness of communication and degree of interaction and commitment between the various stakeholders and interest groups involved with, and affected by, the mining and closure process. This is by nature a horizontal consultative process, whereas the subsequent issues in Questions 2 to 7 are addressed sequentially. (Note that the term ‘project’ is used here to refer to ‘mine closure’). Specific subsidiary objectives include: • • • • •

2. People

Active recourse to communication and engagement mechanisms Agreed mechanisms for resolving differences Established procedures for reporting and independent verification Availability of relevant resources The project is carried out in an atmosphere conducive to transparency and rational assessment of factual data

“Will the well-being of affected communities be maintained (or preferably, further enhanced) following mine closure?” For evaluation of human and environmental impact, the essential measure of success is whether the project is ultimately beneficial or detrimental to human communities and the ambient ecosystem, as determined by agreed performance indicators and criteria. Specific subsidiary objectives include: • • • • • • • • •

3. Natural environment

“Is the long-term integrity and stability of the surrounding biophysical environment assured?” As with human impact, the essential measure of success is whether the project is ultimately beneficial or detrimental to the ambient ecosystem, as determined by agreed biophysical performance indicators and criteria. These issues are addressed widely elsewhere in the closure planning process, with specific subsidiary objectives including: • • • • •

4. Economy

Communities are sufficiently organized to remain viable over the long term Social and cultural activities are maintained, or improved Public and occupational health and safety issues are addressed adequately and standards maintained Infrastructure of affected communities remains adequate for maintaining general well-being Potentially adverse and compounded effects, both direct and indirect, are anticipated and dealt with accordingly Realistic cost estimates are made for any social or cultural change and disruption Accountability for responsibilities, risks and related expenditures is precisely defined and audited Appropriate accounting and agreement on cost of closure, including financial provisions and securities The effects of cultural and social disruption are recognized and kept to a minimum

There is no immediate or long-term threat to the stability and diversity of biophysical systems, or impediments to full ecosystem recovery Long-term ecosystem viability is not affected All possible costs, benefits and risks to the environment are documented and considered during decision-making processes Responsibilities, liabilities and financial provisions are precisely defined Adverse environmental affects are kept to a minimum and mitigation measures are implemented

“Have the costs of mine closure been adequately estimated in relation to the viability of mining operations? How will closure affect the local and regional economy?” Economic aspects of the mining process, including closure provisions, as well as the relative contributions of the public sector and non-commercial activities, for example recreation, all need to be assessed to deliver the most favorable project outcome to financial stakeholders, communities and the environment. Specific objectives include: • • • • •

5. Cultural and natural heritage values 6. Public sector institutions and governance

“Does the closure process either contribute to, or adequately address potential impact on traditional and non-commercial and recreational activities, interests and values in the region?” The issues described above in relation to Question 4 are relevant here, with specific objectives including: • •

Traditional and recreational activities are not restricted, interrupted or endangered Traditional lifestyles are maintained and sites of cultural heritage significance are preserved

“Are legislative and institutional arrangements and resources appropriate and sufficient for ensuring that the closure process complies with best management practices?” The issues described above in relation to Question 4 also apply here, with specific objectives including: • • • •

7. Overall assessment

That financial provisions are adequate for the project The process is efficiently implemented Allocation of both responsibilities and benefits is just and in accordance with previously defined expectations Local and regional community economic objectives are attained The project is aligned with regional and national economic objectives and strategies

The combination of appropriate legislation, market incentives, involvement of volunteer and non-government organizations, and acknowledgement of cultural values provides a basis for good management and governance Provision of resources is adequate and implementation is effective The closure project is designed, during the operations phase, to be implemented as a gradual, rather than abrupt transition. Mutual trust and respect exist between stakeholders and communities regarding closure commitments

“When assessed on the basis of the various stakeholder viewpoints and interests, together with closure performance indicators, is the overall process seen to be beneficial or deleterious? Can the progress and success of the project be monitored in a dynamic way, so as to improve outcomes?” This question is defined so as to integrate the issues represented by the preceding six questions, with a view to ongoing opportunities and challenges for improving the process. This new knowledge can then be applied at all stages of the mining life-cycle (exploration and delineation, beneficiation planning, planning of closure and post-closure activities). Specific objectives are: • • • •

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The full range of options for the project are recognized and evaluated Adequate assessment of various options at the strategic level Comprehensive synthesis of the whole process is prepared and available All stakeholders and affected communities and interest groups are committed to ongoing learning and improvement of the process


APPENDIX 3. INITIATIVES AND RECOMMENDATIONS PROMOTING SUSTAINABLE DEVELOPMENT IN THE MINERALS AND MINING INDUSTRIES The table represents a compilation of project initiatives and recommendations for applying sustainable development principles and guidelines to the mining sector, including closure procedures. Most of these projects date from after the year 2000 and are broadly similar in scope. Industry appears to have favoured the ICMM guidelines and the number of companies adopting their recommendations is steadily increasing. Initiative/Recommendation

Agency or organization

Purpose

Comments

Source

Extractive Industries Review (EIR)

Dr Emil Salim, EIR Secretariat Chair

Develop World Bank funding terms and guidelines

Emphasizes socio-economic impacts

http://go.worldbank.org/ T1VB5JCV61

ICMM Sustainable Development Principles & GRI Guidelines

International Council for Mining and Metals (ICMM) and Global Reporting Initiative (GRI)

Commitment to sustainable production practices; requires compliance with GRI-2002 reporting procedures

Binding for 16 industry members and 23 organizations and agencies, including Euromines. Initiated by MMSD

www.icmm.com

Global Dialogue

Canadian and South African + 23 other governments

Commits governments to global challenges relating to the mining sector

Initiative of the UN/CSD and Johannesburg WSSD/ P46

www.globaldialogue.info

Extractive Industries Transparency Initiative (EITI)

UK Government/DFID

Commits governments and other stakeholders to transparency of process

Supported by World Bank and IMF; instigated by Johannesburg WSSD/P46

www.eitransparency.org

Equator principles

Grouping of merchant banks

Ethical investment strategies and social responsibility

IFC supported

www.equatorprinciples. com

Mining Certification Evaluation Project (MCEP)

BHP, CSIRO, Newmont, Placer Dome, RT, WMC & WWF

Develop process for certification of mining industry according to social and environmental performance

WWF initiative parallel to fisheries and forestry certification schemes. Based on ICMM 10 Principles

www.minerals.csiro.au/ sd/SD_MCEP.htm

DFID = UK Department for International Development BHP = BHP Billiton, Co. CSIRO = Commonwealth Scientific and Industrial Research Organization (Australia) RT = Rio Tinto, Ltd. WMC = WMC Resources, Ltd. WWF = World Wildlife Fund IFC = International Finance Corporation IMF = International Monetary Fund WSSD/P46 = World Summit on Sustainable Development Programme, Program Paragraph 46 UN = United Nations CSD = UN Commission on Sustainable Development


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APPENDIX 4. LEGISLATION APPLYING TO MINING This is not an exhaustive list.

Relations with neighbors Adjoining Properties Act, 13 February 1920/26 Health protection Health Protection Act, 19 August 1994/763 Health Protection Decree, 16 December 1994/1280 Environmental permit and environmental impact assessment Environmental Protection Act, 4 February 2000/86 Environmental Protection Decree, 18 February 2000/169 Act on the Implementation of the Legislation on Environmental Protection, 4 February 2000/113 Act on Environmental Impact Assessment Procedure, 10 June 1994/468 Decree on Environmental Impact Assessment Procedure, 17 August 2006/713 Act on Environmental Permit Authorities, 4 February 2000/87 Government Decision on Environmental Permit Authorities, 10 February 2000/128 Ministry of the Environment Decree on fees payable to regional environment centres, 17 December 2003/1237 Ministry of the Environment Decree on fees payable to environmental permit authorities, 17 December 2003/1238 Ministry of the Environment Decree on fees payable to the Ministry of the Environment, 17 December 2003/1241 Water Act Water Act, 19 May 1961/264 Water Decree, 6 April 1962/282 Government Decision on the discharge into the aquatic environment of certain substances dangerous for health and the environment, 19 May 1994/363 repealed Government Decree on the discharge into the aquatic environment of certain substances dangerous for health and the environment, 23 November 2006/1022 Government Decision on the protection of groundwater against pollution caused by certain substances dangerous for health and the environment, 19 May 1994/364 Act on Water Resources Management, 30 December 2004/1299 Dams and controlled release Dam Safety Act, 1 June 1984/413 Dam Safety Decree, 27 July 1984/574 Air pollution prevention and noise abatement Government Decision on air quality guideline values and sulphur deposition target values, 19 June 1996/480 Government Decision on ozone-depleting substances, 2 April 1998/262 Government Decision on guideline values for noise emission levels, 29 October 1992/993 Government Decree on noise emissions level from equipment for outdoor use, 5 July 2001/621 Government Decree on the sulphur content of heavy fuel oil and light fuel oil, 24 August 2000/766 Government Decree on air quality, 9 August 2001/711

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Radiation Radiation Act, 27 March 1991/592 Radiation Decree, 20 December 1991/1512 Oil pollution prevention Act on Combating Oil Pollution on Land, 24 May 1974/378 Building Land Use and Building Act, 5 February 1999/132 Land Use and Building Decree, 10 September 1999/895 Sanitation and waste management Waste Management Act, 31 August 1978/673 Waste Act, 3 December 1993/1072 Waste Decree, 22 December 1993/1390 Government Decision on information to be provided on hazardous waste and on the packing and labelling of hazardous waste, 29 August 1996/659 Government Decision on oil waste management, 30 January 1997/101 Government Decision on landfill sites, 4 September 1997/861 Government Decision on packaging and packaging waste, 23 October 1997/962 Ministry of the Environment Decree on the list of the most common wastes and of hazardous wastes, 22 November 2001/1129 Council Decision of 19 December 2002 establishing criteria and procedures for the acceptance of waste at landfills pursuant to Article 16 of and Annex II to Directive 1999/31/EC Government Decree on assessment of soil contamination and need for remediation 214/2007 Nature conservation Nature Conservation Act, 20 December 1996/1096 Nature Conservation Decree, 14 February 1997/160 Mining Mining Act, 17 September 1965/503 Mining Decree, 17 December 1965/663 Ministry of Trade and Industry Decision on mining safety instructions, 28 November 1975/921 Ministry of Trade and Industry Decision on mine maps, 27 October 1995/1218 Government Decision on the ordinance for blasting and excavation work, 29 May 1986/410 Shot firer Act, 25 February 2000/219 Shot firer Decree, 25 February 2000/220 Directive 2006/21/EC of the European Parliament and of the Council of 15 March 2006 on the management of waste from extractive industries and amending Directive 2004/35/EC – Statement by the European Parliament, the Council and the Commission


Chemicals, pesticides and explosive substances Chemicals Act, 14 August 1989/744 Ministry of Trade and Industry Decision on explosive materials, 25 February 1980/130 Ministry of Social Affairs and Health Decision on the list of hazardous substances, 24 February 1998/164 Decree on the Industrial Handling and Storage of Dangerous Chemicals, 29 January 1999/59 Explosives Decree, 28 May 1993/473 Act on the Safe Handling of Dangerous Chemicals and Explosives, 3 June 2005/390 Regulation (EC) No 1907/2006 of the European Parliament and of the Council of 18 December 2006 concerning the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH), establishing a European Chemicals Agency, amending Directive 1999/45/EC and repealing Council Regulation (EEC) No 793/93 and Commission Regulation (EC) No 1488/94 as well as Council Directive 76/769/EEC and Commission Directives 91/155/ EEC, 93/67/EEC, 93/105/EC and 2000/21/EC


Civil law Tort Liability Act, 31 May 1974/412 Act on Compensation for Environmental Damage, 19 August 1994/737 Environmental Damage Insurance Act, 30 Januar y 1998/81 Environmental Damage Insurance Decree, 2 October 1998/717 Environmental authorities Act on Municipal Environmental Administration, 24 January 1986/64 Act on the Environmental Administration, 24 January 1995/55 Government Decree on regional environment centers, 4 November 2004/950 Government Decision on the boundaries of jurisdiction and locations of regional environment centers, 25 September 1997/909 Future legislation Draft Government Decree on the environmental protection requirements on rock excavation and rock crushing

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134


Waste classification

Guarantee to ensure/organize waste management

Waste rock is considered non-hazardous waste, though not inert waste, since some of the waste rock can be acid producing. The waste rock disposal areas are classified as non-hazardous waste landfills.

The pond for flotation tailings and neutralization sediments, tailings pond 1, is classified as a hazardous waste dump. The pond for cyanide leaching sediments, tailings pond 2, is also classified as a hazardous waste dump.

Tailings and cyanide leaching sediments are classified as hazardous waste.

Crushed waste rock or other rock which is delivered immediately or after a reasonably brief storage period for use in construction or other such operations is not considered waste, provided that the rock does not contain ore or have acid generation potential.

Disposed waste rock, flotation tailings, neutralization sediments, mixtures of flotation tailings and neutralization sediments, and cyanide leaching sediments are classified as waste.

The guarantees are set so as to cover the shaping and closure costs for the tailings ponds and the waste rock disposal areas and also the costs of monitoring in a case where the operator itself cannot manage it.

Because the dumped material is non-polluting soil (clay, peat) or inert waste produced in the extraction of mineral ores, the Government Decision on landfills does not apply.

A disposal area for materials that are considered permanently inert is considered an inert waste landfill.

Soil and rock whose sulphur content is less than 1.0% are considered inert waste produced in the extraction of mineral ores and can be used for earthworks. Soil and rock used as they are for earthworks either in the mining district, or in road construction or improvement within 36 months of the mine operations being discontinued, are considered a by-product, not waste.

Waste rock and basal moraine whose sulphur content exceeds 1.0% are considered non-hazardous waste.

The mining waste generated in the operations is the waste produced in the excavation of metallic ores.

The guarantee can be partly returned once the North Savo Regional Environment Centre has approved the aftercare work carried out at the site; EUR 10,000 will be retained after this acceptance as guarantee to ensure monitoring and sufficient aftercare.

Bank deposit, bank guarantee or other approved procedure, with the Lapland Regional Environment Centre as beneficiary.

For ensuring construction of the landfill structures and appropriate waste management of the temporarily dumped soil and rock materials.

For the tailings ponds, EUR 15,000 at the start of operations plus EUR 3.7 per additional sq.m in tailings pond 1, and EUR 15.6 per additional sq.m in tailings pond 2. Absolute bank guarantee with the Lapland Regional Environment Centre as beneficiary, bank deposit or other approved procedure.

EUR 1,200,000

EUR 100,000

For the waste rock disposal areas, EUR 15,000 at the start of operations plus EUR 0.013 per each ton of waste rock excavated in the following year.

(The tailings pond is considered a repository of inert non-hazardous waste to which the Government Decision on landfills does not apply.)

Tailings ponds and waste rock disposal areas are considered a repository of inert non-hazardous waste to which the Government Decision on landfills does not apply. The metals contained in the tailings are in poorly soluble form, and the tailings are not acid generating when disposed.

Crushed rock from ore processing and waste rock can be used for earthworks or other construction at the mine site to replace natural materials.

Crushed waste rock and similar materials consistent with the product properties of crushed stone, which immediately or after a reasonably brief storage period are delivered for use in construction or other operations, are not considered waste.

Disposed waste rock, tailings and crushed rock from ore processing are classified as waste which must be treated or used in a place for which an appropriate permit or approval has been obtained.

(In the permit granted on 20 November 2002, the guarantee was considered sufficient to cover the decision concerning the environmental permit for the new tailings pond.)

Permit granted 20 November 2002 (information in parentheses pertains to permit granted for a new tailings pond 6 February 2004), Northern Finland Environmental Permit Authority

Permit granted 6 June 2005, Eastern Finland Environmental Permit Authority

Permit granted 1 November 2002, Northern Finland Environmental Permit Authority

AvestaPolarit Chrome Oy (now Outokumpu Chrome Oy) / Kemi chromite mine

Suomen Nikkeli Oy (Finn Nickel Ltd)/ Exploitation of nickel ore from the Särkiniemi deposit

Riddarhyttan Resources AB / Suurikuusikko gold mine and concentrator

Table 1. Metal ore mines

APPENDIX 5. EXAMPLES OF PROVISIONS IN ENVIRONMENTAL PERMIT DECISIONS REGARDING MINE CLOSURE


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1

The application must contain a detailed plan of the closure of the waste dumps and the removal of other functions, and also of monitoring after closure.

A new application for reviewing provisions in the environmental permit must be submitted by 1 December 2007.

The decision is valid indefinitely. An application to review the permit provisions must be submitted by 20 December 2014.

(The permit is valid indefinitely. An application to review the permit provisions must be submitted by 1 December 2008, together with the ‘main permit’.)

The permit is valid indefinitely. An application to review the permit provisions must be submitted by 1 December 2008.

The only mention is that the permit holder is required to landscape the tailings ponds and the disposal areas for waste rock and crushed rock from ore processing.

(The decision on the new tailings pond notes that the quality of the waste to be deposited in the new pond and the landscaping requirement for the pond cause no changes to the existing situation, referring to the permit decision of 20 November 2002.)

Disposal areas for waste rock and the minerals that cannot be used in the concentration process must be landscaped according to the landscaping plan at the latest when their maximum planned filling level has been reached.

Decision no. 28/05/1, Dnro PSY-2004-Y-148 (13 April 2005). Amendment to provision no. 9 in the environmental permit 77/20/1 issued to the Kemi mine of AvestaPolarit Chrome Oy on 20 November 2002.

Validity of environmental permit

The plan must be updated according to the current situation within one month of extraction being discontinued.

The plan for discontinuing operations must be delivered to the North Savo Regional Environment Centre for inspection within one month of operations starting. The plan must cover at least the following: the disposal area and its foundation and surface structures; water collecting, treatment and conveying structures; and a detailed plan for organizing monitoring.

When operations are discontinued, all machinery, equipment, chemicals, fuels and waste that are potentially harmful to the environment must be removed from the site except for the waste that has a permanent repository at the site.

Discontinuing operations, and aftercare

Open pits and waste disposal areas must be left in a condition conducive to public safety.

Monitoring and landfill aftercare must be continued for at least 30 years after discontinuing operations, or until the environmental burden caused by the mine site can be considered to have ceased.

The permit holder, for the final repositories of waste rock, tailings and sediments, for as long as these can be expected to have potential harmful impacts on the environment, though for not less than 30 years.

Tailings pond 2 must be covered with a watertight surface structure. Before building this, the water seeping from the pond must be recycled through a cyanide removal process until the WAD cyanide level of the water is less than 0.4 mg/l.

Tailings pond 1 must be covered at closure with a surface structure consisting of a seal course at least 0.5 m thick, with a water permeability of no more than 10-8 m/s. This must be topped with a drainage blanket at least 0.3 m thick, with good water permeability, and a growth layer 0.2 m thick.

The tailings ponds, filled to their final level, must be covered once most of the expected sinking of the tailings has occurred, though no later than two years after their use is discontinued. The surface structure must have a seal course at least 500 mm thick, with a water permeability of no more than 3*10-8 m/s. This must be topped with a growth layer of 50 mm, which must be immediately planted with grass. The surface structure must be sloped towards the edges of the pond with a slope of at least 1 in 200.1

Waste rock and basal moraine whose sulphur content exceeds 1.0% must be permanently placed under water layer at the bottom of the open pit when operations are discontinued

In the landscaping of the waste rock piles and tailings ponds, particular attention must be paid to preventing acid generation by minimizing the amount of water and oxygen passing through the disposed material. A growth layer 0.5 m thick must be laid over the sloped and compacted surface of the waste rock areas, consisting of dense moraine on the bottom and peat and/or humus on the top.

Party responsible for aftercare and monitoring

Landscaping and covering of waste rock piles and tailings ponds

Permit granted 20 November 2002 (information in parentheses pertains to permit granted for a new tailings pond 6 February 2004), Northern Finland Environmental Permit Authority

Permit granted 6 June 2005, Eastern Finland Environmental Permit Authority

Permit granted 1 November 2002, Northern Finland Environmental Permit Authority

AvestaPolarit Chrome Oy (now Outokumpu Chrome Oy) / Kemi chromite mine

Suomen Nikkeli Oy (Finn Nickel Ltd)/ Exploitation of nickel ore from the Särkiniemi deposit

Riddarhyttan Resources AB / Suurikuusikko gold mine and concentrator

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EUR 10,000 guarantee to the Southwest Finland Regional Environment Centre to ensure appropriate care and landscaping for the area. The guarantee only applies to the rehabilitation of tailings and waste rock areas classified as waste.

The waste rock (waste title 010102) disposal area is considered a landfill for inert rock waste.


Waste rock, stripping soil and tailings must primarily be reused.

The Government Decision on landfills does not apply to the stripping soil and tailings disposal areas.

The tailings are classified as inert non-hazardous waste produced in the extraction and concentration of mineral ores, as referred to in section 2 of the Government Decision on landfills.

The stripping soil and waste rock are classified as non-hazardous, inert soil and rock waste.

Absolute bank guarantee, with the Kainuu Regional Environment Centre as the beneficiary, or a bank deposit.

The waste rock disposal area is a nonhazardous waste landfill.

Mica schist which contains no sulphides and which is consistent with the product properties of crushed stone, and which is immediately or after a reasonably short period of storage delivered for use in construction or other operations is not considered waste.

The disposed waste rock and soil are classified as waste (title 010101, waste produced in the extraction of metallic minerals).

The guarantee is set so as to cover the costs of landscaping and closure of the waste rock disposal area and monitoring during aftercare and costs in a case where the operator is unable to manage this.

EUR 900,000

The permit holder, for as long as the area can be assumed to have a harmful impact on the environment, though not for less than 30 years.

A guarantee approved by the Southeast Finland Regional Environment Centre (bank guarantee or deposit certificate) to ensure the fulfillment of the obligations regarding disposal areas and aftercare.

The permit holder must manage aftercare for stripping soil and tailings areas for as long as these are found to cause harmful impacts on the environment, though not for more than 30 years after the operations at the site end. If the disposal areas are still causing harmful impacts on the environment 30 years later, the permit authority can rule that the aftercare responsibility will continue beyond that limit.

After landfill use is discontinued, the area must be rehabilitated and landscaped as detailed in the permit application. The landscaping must be executed as the disposal proceeds, as far as possible.

Permit 23 September 2002, Northern Finland Environmental Permit Authority

Lahnaslampi talc quarry waste rock disposal area extension

Mondo Minerals Oy

EUR 200,000

Permit 17 October 2002, Eastern Finland Environmental Permit Authority

Permit 4 July 2003, Western Finland Environmental Permit Authority

The maximum landfill volume is about 2,400,000 tons, the final height is about 60 m, and the slope is 1 in 1.5 or more.

Lappeenranta limestone quarry and calcite and wollastonite concentrators

Parainen limestone quarry waste rock disposal area, Hundbana

Guarantee to organize/ ensure waste management


Nordkalk Oyj Abp

Nordkalk Oyj Abp

Table 2. Industrial minerals mines

The provisions of the environmental permit stipulate further investigation of the composition of the waste rock, its solubility and other properties relevant to its disposal in a landfill. The waste classification and landfill disposal of the waste rock will be decided on the basis of this investigation.

As approved by the Regional Environment Centre.

EUR 500,000

Under the plan approved by the authorities, the impact on watercourses will be monitored until it is found that the disposal areas no longer have an impact on the environment.

Permit 16 November 2001, Eastern Finland Environmental Permit Authority

Lipasvaara talc and nickel mine

Mondo Minerals Oy


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Permit 17 October 2002, Eastern Finland Environmental Permit Authority

Permit 4 July 2003, Western Finland Environmental Permit Authority

Rehabilitation and landscaping must be carried out as specified in the plan appended to the permit application. Slopes and levels will be covered with a 30-220 mm layer of gangue, topped with moraine with humus content or clay. Alternatively, compost peat from Paroc Oy Ab’s rock wool plant can be used. Landscaping should begin from the bottom once the disposal has progressed so far that there is a sufficient amount of surface area available.

A record must be kept of waste rock disposed, showing the volumes and times of disposal.

Lappeenranta limestone quarry and calcite and wollastonite concentrators

Parainen limestone quarry waste rock disposal area, Hundbana

*When the permit decision was granted, the neighbors voiced their unanimous opposition to planting trees, and the environmental permit authority entered in the inspection minutes that the area is to be landscaped using grass.

Stripping soil: The earthwork protecting the dumping area must be landscaped with trees and grass at the construction stage. The protective line of trees outside the earthwork must consist, at least in part, of coniferous and deciduous saplings grown to a minimum height of 4 to 5 m.* Once the dumping area reaches its final height of +82 m, the area must be shaped and landscaped with plantings to merge with the landscape and terrain. The surface must be covered with a sufficient growth layer and shaped so that no water-collecting depressions remain. Aftercare for the dumping area must be implemented stagewise as the area reaches its final height.

Tailings pond: The outer slopes of the perimeter dams must be landscaped to merge with the environment as the dams are raised. Once the dam reaches its final height of +82 m, trees and shrubs must be planted with a view to landscaping and dust binding.

If operations will be discontinued before the permit decision is revised, the permit holder must submit to the Environment Permit Authority an application with a plan on the aftercare measures required because of the discontinuation, at least eight months before the discontinuation.

Once the mine is closed, the site must be cared for so that it causes no danger or harm to the environment or to human health.

Nordkalk Oyj Abp

Nordkalk Oyj Abp

Permit 23 September 2002, Northern Finland Environmental Permit Authority

Lahnaslampi talc quarry waste rock disposal area extension

Mondo Minerals Oy

The aftercare for the disposal areas must be carried out within three years of the discontinuation of disposal. Aftercare for the northern disposal area must be conducted in stages while the disposal area reaches its final height, as far as possible.

The surfaces of the disposal areas must be shaped so that no water-collecting depressions remain. Slopes and terraces must alternate so that no slope is more than 40 m long. According to the approved plan, the moraine layer on the surface structure will be about 1 m, and the growth layer will be about 0.2 m thick.

The waste rock disposal areas must be managed and landscaped by covering them with moraine and growth layers containing clean soils.

According to the plan approved by the authorities, the settling ponds will be covered with dense moraine or converted into a wetland where vegetation will be used to bind any metals present.

Once the mine operations are discontinued, the site must be given aftercare so that within three years it is rendered into a state where it is no longer dangerous or harmful to the environment or to human health.

Aftercare for the waste rock disposal areas must be continued for as long as they are found to have harmful impacts on the environment, though not for more than 30 years after operations are discontinued. If, after 30 years, the disposal areas are still found to have harmful impacts on the environment, the environment permit authority can rule that the aftercare responsibility will continue beyond that limit.

Permit 16 November 2001, Eastern Finland Environmental Permit Authority

Lipasvaara talc and nickel mine

Mondo Minerals Oy

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The permit is valid indefinitely. An application to review the permit provisions must be submitted by 31 December 2010.

The permit is valid indefinitely. An application to review the permit provisions must be submitted to the environment permit authority by 30 September 2009.


Once the mine operations have been discontinued, aftercare must be provided so that within three years the site no longer poses a danger or harm to the environment or to human health.


The permit is valid indefinitely. An application to review the permit provisions must be submitted by 1 April 2009.

If operations will be discontinued before the permit decision is revised, the permit holder must submit to the Environment Permit Authority an application with a plan on the aftercare measures required because of the discontinuation. The plan must cover aftercare for quarries, disposal areas and settling pools, and the processing of the sludge accumulating at the bottom of the pools. The plan must further detail water treatment and conveyance at the mine site once aftercare has been implemented, and a monitoring plan.

Aftercare for the disposal area must progress in stages while the area reaches its final height. The disposal area must be landscaped using clean soils and a sufficient growth layer, and the surface must be shaped so that no water-collecting depressions remain. The parts of the disposal area that have reached their final height must be landscaped so as to merge with the landscape and terrain.

The provisions of the environmental permit also call for more investigations into the composition, solubility and other properties of the waste rock and the powdered soapstone.

The waste rock and the stripped soil are classified as waste, and the waste rock disposal area is considered a landfill. Non-hazardous soil and rock waste (stripping soil and waste rock) should primarily be reused.



The purpose of the guarantee is to ensure fulfillment of the obligations regarding the soil and rock disposal areas and the carrying out of measures required by the discontinuation of operations and aftercare.

As approved by the Regional Environment Centre (bank guarantee or deposit certificate).

EUR 80,000

Guarantee to organize/ensure waste management

If operations will be discontinued before the permit decision is revised, the permit holder must submit to the Environment Permit Authority an application with a plan on the aftercare measures required because of the discontinuation, at least six months before the discontinuation. The plan must cover aftercare for open pits, disposal areas and settling ponds, and the processing of the sludge accumulating at the bottom of the ponds. The plan must further detail water treatment and conveyance at the mine site once aftercare has been implemented, and a monitoring plan.

A new application to review the provisions of the environmental permit must be submitted by 31 October 2009.

The permit holder must manage aftercare for the waste rock disposal areas for as long as they are found to have a harmful impact on the environment, though for not more than 30 years after operations are discontinued. If, after 30 years, the disposal areas are still found to have a harmful impact on the environment, the environment permit authority can rule that the aftercare responsibility will continue beyond that limit.

A new application to review the provisions of the environmental permit must be submitted by 31 December 2003.


Permit 3 May 2002, Eastern Finland Environment Permit Authority

Soapstone extraction in Koskela mining district

Tulikivi Oyj

Table 3. Natural stone quarries as per the mining act



139

Ministry of Trade and Industry (MTI) Regional Environment Centre or Ministry of the Environment

Planning is managed by the local authority

Mining Act (503/1965) as amended (1625/1992)

Act on Environmental Impact Assessment (468/1994) as amended (267/1999)

Land Use and Building Act (132/1999)

Claim

EIA

Planning, decision on municipal planning needs

Ministry of Trade and Industry (MTI) Safety Technology Authority (TUKES)



Notification of mine operations

Mine map

MTI Decision on mine maps (1218/1995)

Ministry of Trade and Industry (MTI)


Mining district application

Annually for the duration of the concession

At the same time as the claim is submitted, or during the claim period; EIA report must be appended.

Component master plan drawn up in parallel with EIA procedure

Before the mining district application is submitted if the proposed volume of material to be extracted is equal to or greater than 550,000 tonnes per are, or if the surface area of the quarry is greater than 25 hectares.2

Before more extensive exploration is launched

Exploring stage, before sampling

Application time

Topographic and geological surface map, with horizontal and vertical sections

Has mining been carried out in the mining district, and if so, a report on the extent, nature and results of the operations

Includes a description of the exploration and its findings, a plan of use for the mining district and its area, a cadastral register extract, parties involved, statement from the local authority

Two stages: assessment programme and assessment report (see the EIA guide)1

Contact information for claimant, data on area, assumed minerals to be exploited, and estimate of exploration required

Freeform notification

Principal content

The application launches a mining district process which results in the setting up of a mining district and the granting of a concession; MTI can decide at its discretion whether the EIA report needs to be appended to the general mine plan.

Planning needs must be investigated

EIA report must be appended to permit applications; this also includes the environmental safety of mine closure and by-products.

Further information

2

Can be applied to other projects, too, on a case-by-case basis if the anticipated environmental impact is significant.

Salminen R., Heikkinen P., Nikkarinen M., Parkkinen J., Sipilä P., Suomela P., Wennerström M. (1999) Ympäristövaikutusten arviointimenettelyn opas kaivoshankkeisiin. Kauppa- ja teollisuusministeriön tutkimuksia ja raportteja 20/1999, Teknologiaosasto. 80 s. [Ministry of Trade and Industry]

1

Landowner or local land registry office


Exploring: Notification of sampling

Land Use and Building Decree (895/1999)

Application processed by

Legal reference

Permit or notification

Table 1. Permits to be obtained and notifications to be made before taking the decision to establish a mine.

Both mining legislation and environmental protection legislation require a permit procedure. There are also permits and notifications stipulated in the legislation on land use, construction and chemicals. In addition to the legislation cited here, the Antiquities Act may require notification to be made to the Archaeological Commission, running a canteen requires a notification to the municipal health inspector, etc. Existing and pending legislation governing mining is described in chapter 3.

- Permits and notifications before the decision to establish a mine is taken - Permits and notifications related to operations after the decision to establish a mine is taken - Permits and notifications related to discontinuation of operations

Tables 1-3 list the principal permits and notifications governing mine operations. These are divided as follows:

APPENDIX 6. PERMITS GOVERNING MINE OPERATIONS

140


Safety Technology Authority (TUKES)

Environmental Permit Authority

Ministry of Trade and Industry Decision on mine safety instructions (921/1975) as amended (1187/1995)

Environmental Protection Act (86/2000),

General plan for mine operations

Environmental permit (including matters related to waste management, groundwater, soil and air protection)

Dam safety monitoring programme and risk report

Act on the Safe Handling of Dangerous Chemicals and Explosives (390/2005)

Safety report or operating principles document

Dam safety instructions (Ministry of Agriculture and Forestry 1997)

Dam Safety Act (413/1984)


Decree on the Industrial Handling and Storage of Dangerous Chemicals (59/1999)


Decree on the Industrial Handling and Storage of Dangerous Chemicals (59/1999)

Site rescue plan

Permits for the handling and storage of dangerous chemicals

Permits for the handling and storage of dangerous chemicals

- other construction



In good time before the dam is completed. Must be approved before the dam is taken into use. Date of submission to the authorities depends on the dam classification.

Determined on the basis of the volume of chemicals and how dangerous they are


Others: Local civil protection authority

In cases of large-scale industrial handling and storage of chemicals

For small-scale handling and storage of chemicals, before storage is started

For large-scale handling and storage of chemicals, before storage is started

Before construction, or before substantially changing a building or its purpose

Part of the environmental permit application

Before mining is started and whenever substantial changes are made that will increase emissions or risks

Before mining is started. Must be updated at any time when substantial changes are made to the mine.

Application time

New production facilities: TUKES

Local civil protection authority


Local building authority

Land Use and Building Act (132/1999)

Building permits

- concentrators, offices, storage and other buildings


Water Act (264/1961)

Water Act permit (water conducting, water extraction, waterway changes)

Environmental Protection Decree (169/2000)


Legal reference


Monitoring of structures and water level, measurements, inspections, etc.

The content of the operating principles document is described in Appendix III of Decree 59/1999, and the content of the safety report is described in Appendix IV.

Responsible persons, measures for foreseeable dangers, notification to the authorities, personnel training (Appendix VI of Decree 59/1999).

Permit application content described in Appendix II to Decree 59/1999

Report on possession of the building site, principal drawings of the building

Identification data, location data, operations, environmental load, BAT report, impacts, monitoring, damage prevention

Limits of soil extraction, surface water and groundwater arrangements, excavation execution, access shafts and exit routes, dewatering and ventilation, location of industrial and waste dumping areas, mine building schedule.

Principal content

Table 2. Permits to be obtained and notifications to be made after the decision is taken to establish a mine

Application instructions can be found on the environmental administration website. Mining may not be started before the permit has entered into force. The EIA report and a statement from the contact authority must be appended. The permit application must include a closure plan and a report on the environmental safety of by-products.

It is recommended that the application includes a preliminary closure plan. Mine inspection (TUKES) at least once a year.

Further information


141

Annually for the duration of the concession


Ministry of Trade and Industry


Ministry of Trade and Industry Decision on mine safety instructions (921/1975) as amended (1187/1995)



Permits for storing explosives, other permits regarding explosives

Notification of mine operations

Mine map

When lifting equipment is permanently withdrawn from use

Ministry of Trade and Industry


Mining Act (503/1965)


Notification of relinquishing concession

Mine map

By May 1 in the year following the discontinuation of mine operations

After mine operations have been discontinued

Environmental administration instructions and forms can be found at http://www.ymparisto.fi/

Ministry of Trade and Industry Decision on mine maps (1218/1995)


Ministry of Trade and Industry Decision on lifting equipment in mines

Notification on withdrawal of lifting equipment

When lifting equipment is permanently withdrawn from use

When planning the rehabilitation action. Notification no later than 30 days before the cleaning action.

Regional Environment Centre

Environmental Protection Act (86/2000)

Environmental permit for rehabilitation of contaminated areas or notification of cleaning

Environmental Protection Decree (169/2000)

6 to 8 months before closure at the latest


Required for the environmental permit for mines as per the Environment Protection Act

Aftercare plan

Application time


Legal reference


Table 3. Permits to be obtained and notifications to be made in relation to mine closure

Ministry of Trade and Industry Decision on mine maps (1218/1995)

In good time before storage is begun


Ministry of Trade and Industry Decision on lifting equipment in mines (372/1969) as amended (1188/1995)

Notification on withdrawal of lifting equipment

Before new lifting equipment is taken into use


Ministry of Trade and Industry Decision on lifting equipment in mines (372/1969) as amended (1188/1995)

Notification on lifting equipment

Application time


Legal reference


Topographical and geological surface map with horizontal and vertical sections

Written notification to the Ministry of Trade and Industry

Freeform notification

Contact information, data on the contaminated area and the contamination, cleaning objective and methods, environmental impacts of the cleaning; permit application must include BAT study, monitoring, etc.

Detailed plan concerning the discontinuation of mine operations

Principal content

Topographic and geological surface map, with horizontal and vertical sections

Has mining been carried out in the mining district, and the extent, nature and results of the operations

Type and amount of explosive to be stored, location map and plans of storage facility

Principal content

The concession expires when the notification is received by the Ministry.

Permit application and notification forms are available on the environmental administration website. It takes more time to process a permit application than a notification.

Further information

Initial inspection, annual inspection by TUKES

Further information

APPENDIX 7. CONTAMINATED SOIL LEGISLATION AND AMENDMENTS

Before 1 April 1979 (before the Waste Management Act entered into force) • who is responsible ◦ holder of the area > obligation to present a waste management plan as per the Environment Protection Act ◦ party guilty of littering, but this provision cannot be applied to an operation which ceased completely before the Waste Management Act entered into force (Supreme Administrative Court, 12 June 2001 (1414)) • contemporary legislation (Water Act, Mining Act, etc.) 1 April 1979 to 31 December 1993, Waste Management Act (673/1978) • obligation to present a waste management plan (section 21) ◦ who is responsible • holder of the area • prohibition on littering (sections 32 and 33) ◦ ‘substance’ added in amendment in 1987 (203/1987) ◦ who is responsible • polluter • holder of the area • local authority, but only if the polluting party cannot be established and the incident has not occurred in a densely populated area and is not covered by the obligations of the public road keeper (the road itself, shoulders and adjacent areas)

1 January 1994 to 28 February 2000, Waste Act (1072/1993) • the Waste Decree used to have (1997-2000) a provision whereby the provisions on approval procedure in the Waste Act do not apply to inert soil and waste rock produced in mine operations and used or processed in those operations or mine operations elsewhere, provided that the waste is used or processed according to a plan approved as per the Mining Act • who is responsible ◦ polluter ◦ holder of the area ◦ local authority From 1 March 2000, Environmental Protection Act (86/2000) • exception to permit procedure (institutional or professional treatment of waste) ◦ section 28(2) paragraph 4 of the Environmental Protection Act > section 4(1) paragraph 2 of the Environmental Protection Decree ◦ the use or processing of clean soil and waste rock according to an approved plan which fulfils the requirements of the Waste Act does not require an environmental permit ◦ the specific exception in the Waste Decree pertaining to mine operations has been repealed • who is responsible ◦ primarily the polluter ◦ holder of the area ◦ local authority

Time dimension of waste legislation Obligation to present a waste management plan and ban on littering as per the Waste Management Act (WMA) -retroactivity - obligation to present a waste management plan is retroactive, Environmental Protection Act (EPA) procedure is applied - prohibition on littering, on the other hand, cannot apply to operations which ceased completely before the Waste Management Act entered into force EPA WA (Waste Act)

Littering remains in WA

1 Jan 1994 WA

1 Mar 2000 EPA

WMA (substance) WMA obligation to present waste management plan + littering ban 1 Apr 1979 WMA

142

1 May 1987 WMA (substance)


APPENDIX 8. EXAMPLE OF HOW TO COMBINE A PARTIAL DISPOSITION PLAN AND A MINE PROJECT

The partial disposition plan for the Suhanko mine area Suhanko is an area covering the north-western part of the municipality of Ranua and the eastern part of the municipality of Tervola. The exploitation of platinum deposits was planned for there. The local authorities of Ranua and Tervola jointly commissioned a partial disposition plan for the mine area, drawn up by JPTransplan Oy / Jaakko Pöyry Infra in Oulu. The plan area covers the deposits as well as the proposed locations of the concentrator, offices, maintenance and upkeep facilities, and waste rock and tailings areas. There are also areas reserved for roads and waterway arrangements. The partial disposition plan covers an area of about 52 sq.km. The partial disposition plan was prepared in parallel with the EIA procedure. The reports and scenario impacts produced in the EIA procedure were used in the planning process. The partial disposition plan process included these stages: 1) Decision by municipal boards on drawing up a partial disposition plan 2) Initial meeting and briefing 3) Presenting the draft stage 4) Draft partial disposition plan on public display 5) Hearings of landowners and other parties 6) Request for statements from the Regional Council, the Regional Environment Centre and bordering municipalities 7) Proposed partial disposition plan on public display 8) Approval by municipal boards

There were also several negotiations and talks between authorities during the work, which was started in autumn 2001 and finished with the municipalities approving the plan in autumn 2003. The purpose of the planning was to reserve an area for mine operations and to find the best land-use solution for placement of functions. There was no existing civil engineering infrastructure in the area. The anticipated lively traffic, heavy transport and large quantities of energy and water required for the mine operations needed arrangements of their own. The planning process was governed by the Land Use and


Building Act as relevant for the objectives of land use planning (section 5) and by national land use objectives. The area covered by the plan was designated as agricultural and forestry land (MT) in the regional plan in Ranua, whereas Tervola is covered by the Lapland sub-regional plan, where the area was designated as principally a timber-producing area (MT1). The proposed Lapland regional plan highlights the rich deposits of valuable metals in northern Finland and how important their exploitation is for the region; it also highlights the importance of restoring mine areas to a harmless and natural state following the discontinuation of mine operations. The plan description of the component master plan details the purpose of the planning, its objectives and options, and also describes the natural conditions, land use and community structure, traffic and business in the area and how the proposed project would affect them, including social impacts. The description also links the plan to other planning and to national land use plans and it contains a participation and assessment plan. The partial disposition plans were mainly determined by the land use requirements of mine operations, which in turn were determined by the functional and economic requirements of mine operations and by nature and landscape conservation aspects. For example, options for the placement of the tailings pond and transport access routes were weighed in the EIA procedure. The general description of the partial disposition plan notes that the nature of the operations is such that damage will be caused to the area and its vicinity, both to the natural environment and to the landscape. The placement of functions is largely indicative. The area is marked on the plan as EK (mine area). Special markings denote the locations of intensive soil extraction, waste rock areas, tailings areas, the quarry, buildings and dam basin and possible expansion of the mine. The plan description of the partial disposition plan refers to statutory provisions as regards aftercare measures but notes that mine closure and aftercare actions should be planned at the project planning stage. At the moment, the expectation is that the Suhanko area will be turned over to timber production after the mine is closed.

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APPENDIX 9. SULPHIDE OXIDATION PROCESSES

The oxidation of sulphide minerals is a critical process with respect to the environmental management and potential use of waste rock and tailings. Sulphide minerals present in waste rock and tailings will tend to oxidize when exposed to oxygen and water. Mechanisms for oxygen transport into tailings or water rock piles include diffusion of oxygen, driven by partial pressure differences between the atmosphere and air trapped within porous material, transport of dissolved oxygen via percolation of rainwater, or infiltration through

thermally driven convection and wind-generated turbulence. The diffusion coefficient of oxygen in air is approximately four orders of magnitude greater than in water (Robertson et al. 1997). Oxidation of sulphides generates sulphate anions and free hydrogen radicals that will tend to promote acidity. Typical sulphide minerals include pyrite (FeS2) and pyrrhotite (FeS1-x). A series of simple balanced oxidation reactions for pyrite (Mitchell 2000) are presented below (Equations 1-4).

2 FeS2(s) + 7 O2(aq) + H2O(l)

→

2 Fe2+(aq) + 4 SO42-(aq) + 4 H+(aq)

(1)

2 Fe2+(aq) + ½ O2(aq) + 2 H+(aq)

→

2 Fe3+(aq) + H2O(l)

(2)

FeS2(s) + 14 Fe3+(aq) + 8 H2O(l)

→

15 Fe2+(aq) + 2 SO42-(aq) + 16 H+(aq)

(3)

↔

+

(4)

3+

Fe

(aq)

+ 3 H2O(l)

The oxidation of pyrite in the absence of the ferric iron (equation 1) is a slow process in nature. Reaction 2 is also slow in an acid environment unless mediated by a biological catalyst, in which case reaction progress and oxidation of Fe2+ to Fe3+ may be enhanced by up to six orders of magnitude. Ferric iron is a highly efficient oxidant, which reacts with pyrite (equation 3), other sulphides and with water (equation 4) resulting in the formation of e.g suphates and production of acidity.

Fe(OH)3(s) + 3 H

(aq)

The pH of mine waters discharging from waste rock and tailings facilities is largely determined by a dynamic equilibrium between acid-producing and buffering reactions. All materials containing sulphide minerals, such as pyrite, have the propensity to generate free protons, and thus acidity. Nevertheless, acidic mine waters (Acid Rock Drainage = ARD; Acid Mine Drainage = AMD) will only form where the neutralizing effect of alkaline reactions is insufficient.

References Mitchell, P. 2000. Prediction, Prevention, Control and Treatment of Acid Rock Drainage. In: Warhurst, A. & Noronha, L. (eds.): Environmental policy in mining – Corporate strategy and planning for closure. Lewis Publishers, Boca Raton, Florida. 513 s.

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Robertson, J.D., Tremblay, G.A. & Fraser, W.W. 1997. Subaqueous tailings disposal: A sound solution for reactive tailings. Fourth International Conference on Acid Rock Drainage: Vancouver, B.C. Canada, May 31-June 6 1997: Proceedings, Vol. 3. pp. 1029-1041.


APPENDIX 10. HYDROGEOLOGICAL AND GEOCHEMICAL MODELLING

The following sections provide a general summary of numerical hydrogeological and geochemical modelling, a review of available modelling codes and background information on the appropriate input parameters and boundary conditions required for modelling, with particular emphasis on applications in mine closure.

Hydrogeological modelling Simulation of flow and transport methods used in hydrogeological modelling may be based on either analytical or numerical solutions, or some combination of both approaches. However, in every case, the underlying mathematical calculations rely on the principle of mass balance within groundwater or, if appropriate, within both the saturated and unsaturated zones. A dynamic mass balance represents the interaction between groundwater (and vadose water) flow, infiltration and recharge, and discharge into surface waters. The overall mass balance is also influenced by human activities such as groundwater extraction, or infiltration. Groundwater flow and particle transport are governed primarily by hydraulic parameters of aquifers (and aquitards), but for the purpose of modelling, mathematical equations also need to be specified for the boundary conditions to the model. Flow within the model, or solution domain, is generally based on Darcy’s law. The mathematical derivation of mass balance equations and background theory is considered in numerous textbooks, such as Bear (1979), Bear and Verruijt (1994) and de Marsily (1986). In most cases, the equations describing groundwater are based on differential solutions. Broadly speaking, the analytical approach to modelling produces robust and quantitative mathematical solutions for flow and transport in precisely quantified, though extremely simplified systems, for which boundary conditions and physical parameters are well-constrained. Conversely, numerical models can simulate processes with more complex model geometry and distribution of parameters, but the flow and transport is calculated using relatively simplified (so called discrete) mass balance equations. Depending on properties of flow medium, numerical flow and transport models can be subdivided into three broad groups comprising equivalent porous media, dual porosity media or discretely fractured media models. The various differences between these methods are described in detail in standard texts and references (see Bear and Verruijt 1994, de Marsily 1986).


The analytical modelling approach is typically used for estimation of the hydraulic properties of geological units and can provide constraints on, for example, hydraulic conductivity and groundwater recharge and discharge rates and volumes, or areas affected by downdraw related to pumping. Such results can then be used as input parameters and boundary conditions for more complex numerical simulations. Analytical solutions for groundwater flow into open pits and underground workings have been calculated in connection with mine closure studies (Hanna et al. 1994, Marinelli and Niccoli 2000), as has estimations of the rate of filling of decommissioned open pits (Fontaine et al. 2003). In addition to these applications, analytical models can be use to evaluate particulate transport and changes in concentration in flowing groundwater (e.g Ogata 1970). One of the main advantages of analytical modelling is the precision with which the underlying equations allow quantitative results, for example extent of downdraw, or species concentration, to be obtained. General summaries of analytical methodology and their application in determining hydraulic parameters are provided by Lohman (1972) and Kruseman & DeRidder (1991). Analytical modelling solutions may also be used in so-called semi-analytical process modelling to substitute for computationally demanding numerical sub-processes. Semi-analytical models have been developed for estimating risk of groundwater contamination and for metal migration in groundwater. Examples of semi-analytical models include the socalled analytical element-based codes TWODAN and MODAEM (Strack 1989, Haitjema 1995), and FRACTRANS, which was developed for bedrock fracture analysis (Sudicky & McLaren 1992). Numerical flow and transport model calculations may be based on finite-difference, finite-element or finite-volume methods, relying on diverse computer packages that solve according to various combinations of differential equations and matrix algebra. Commercially available finite-difference applications include various graphical interfaces based on the MODFLOW code of McDonald and Harbaugh (1988), such as PMWIN, GMS, and Visual Modflow, and related reactive transport codes (including MT3D, MODPATH; RT3D); a further code SWIFT is designed for simulating transport of heat, saline fluids, and radionuclides as well as groundwater flow, while the TOUGH package (Pruess 1991) is capable of modelling computational intensive processes, including more specialized ap-

145

plications (TOUGHAMD and TOUGHREACT), for mine-related environmental problems. Examples of modelling packages based on the finite-element approach include FEMWATER, FEFLOW, FLONET and FRAC3DVS (Lin et al. 2002, Therrien et al. 1999). The finite-volume method of calculation is rather less common, but is used for example in the PCGEOFIM-code (Müller et al. 2003), which has in fact become widely accepted in Germany in particular, as a standard tool for rock mechanics and evaluation of groundwater flow in abandoned quarries and in mine environments during closure. All these programs are flexible in terms of modifying system set up and have additional modules permitting simulation of two-phase porous flow. In addition, the FRAC3DVS and SWIFT codes are able to solve for discrete fracture-related flow. Numerical modelling techniques are also capable of simulating advection and transport of gas groundwater flow, heat transfer and radionuclide migration. Numerical simulations of processes relevant to mine closure include evaluations of the rate of filling of open pits (Toran and Bradbury 1988) and transport within tailings impoundments (Johnson 1993). The choice of hydraulic parameters for use in numerical modelling depends largely on the whether flow is saturated, within the phreatic zone, or above the water table in the vadose zone, or whether or not particulate material is being transported by water. In general, some constraints on hydraulic properties are required, notably parameters relating to the permeability and storage capacity of groundwater aquifers and formations, (hydraulic conductivity or permeability, storage coefficient and specific yield etc.), and also to the water table (hydraulic head or potential). Hydraulic parameters are themselves influenced by the medium, through which fluid flows, so that information will be required concerning geological properties such as grain size distribution, thickness and composition of stratigraphical and lithological units, depth to bedrock and fracture density and patterning in underlying bedrock. In addition to the above information, transport simulations require knowledge of the concentration of contaminants within the fluid and other attributes affecting their behaviour, such as dispersion and adsorption. Depending on the nature of the investigations, field or laboratory measurements are usually required for defining relevant and realistic values for model input parameters and boundary conditions, for example characterization of surficial sedimentary materials, depth to the water table and flow rates at natural discharge sites, geophysical surveys, pumping and other hydraulic tests, groundwater analysis and tracer experiments. In addition generalization and assessment of field and laboratory based hydraulic results

146

is usually performed with geostatistical analysis and interpolation methods. As noted above, modelling of groundwater flow requires specification of boundary conditions as well as flow-related parameters. Boundary conditions are defined according to mathematically prescribed interactions between the model and the external environment. For example, in groundwater flow models, boundary condition values are commonly based on measured hydraulic head or groundwater flow rate, but can also be defined from groundwater seepage, topology of the phreatic surface, or lakes, wells, drainage channels, natural streams or any other features that influence groundwater discharge or infiltration. Models need to be calibrated against a reference state to ensure stability and that the resolution of the model simulation is consistent with the precision of the input data. For calibration purposes the calculated results of a simulation (for example depth to water table) are compared with actual measured values (such as water levels in observation wells) and relevant variables (for example hydraulic conductivity) may then be modified accordingly, to yield more realistic approximations. Calibration is routinely performed with programs that offer automated mathematical optimization (such as MODFLOW 2000, PEST, UCODE). Optimization procedures can also be used during inverse modelling to better define the relevant parameter space for poorly or inadequately constrained variables. Automated calibration optimization also provides a statistical analysis of input and background variables and their influence on model results, which can then be used in evaluating inherent uncertainties or deficiencies in the modelling process.

Geochemical modelling Geochemical models are intended to simulate natural chemical processes within a geological context and as in the case of hydrogeological modelling, the same principles of mass and energy conservation and balance apply. Geochemical models are typically thermodynamically and kinetically based and may be used for both forward and inverse simulations. Conceptually, inverse and forward modelling approaches differ in that forward models are used to attempt to predict the future behaviour and final state of a system, by specifying premises and conditions for the initial state, and then simulating the effect of a given process. Examples of the forward modelling approach would include the effect of dissolution of a particular mineral species on water chemistry over time. In contrast, the inverse modelling approach is used primarily to deduce the nature of system processes and pathways, with


reference to the observed final state and an inferred initial state. A typical example of inverse modelling would be to determine the weathering or precipitation mechanisms for a mineral species, based on analyses of water chemistry from two or more points along the same flow path. Geochemical models can be further categorized on the basis of their properties and underlying principles into speciation-solubility models, reaction mechanism models, mass balance models or coupled reactive transport models. Thermodynamic speciationsolubility models can be used to ascertain ionic and molecular concentrations and activities in solution, as well as degree of saturation of solutions and progress and direction of equilibrium reactions. In addition, this approach allows estimation of partitioning of stable species or components between grain surfaces in equilibrium with solution (= chemically bonded ions and complexes) or ion exchangers (= physically bound ions and complexes). Results of speciation-solubility models can be used to indicate which reactions are thermodynamically favorable. However, because they do not take reaction rate into account, they may derive an equilibrium state for a system, which is for kinetic reasons, impossible to attain. While geochemical models based on thermodynamics alone require interpretation by an expert user familiar with relevant chemical processes, calculated results, for example of molality, can be used as input data for more complex models (Zhu & Anderson 2002). As an illustration of geochemical modelling applications relevant to mine closure investigations, it is possible for example, to determine with speciation-solubility models as the basis for mass balance modelling, which mineral species are susceptible to dissolution or precipitation, or ascertain whether contaminants present in surface or ground waters are bioavailable or in toxic form. Reaction mechanism modelling can be used to define an evolving sequence of successive equilibrium states for a given geochemical system, representing either continuous or episodic mass transfer between various phases, or continuous addition or removal of a given reactive component from the system. Such models are therefore ideally suited to investigating dissolution and precipitation of mineral phases, the characterization of water chemistry resulting from mixing from different sources, or for determining effect of retention of substances and ion exchange reactions. Each of these modelling strategies can also treat geochemical systems as either closed or open system. In the former case, it is assumed that the products formed during reactions will be involved in subsequent processes, whereas for open systems, reaction products are removed from the system and no longer participate in


subsequent reactive processes. Reaction mechanism modelling may be used in mine environment studies, in particular in relation to planning and discriminating between alternative site remediation options. For example, model simulations may indicate how the availability of oxygen might influence oxidation of sulphide minerals. Thus, using a range of alternative scenarios, it may be possible to evaluate the effectiveness of tailings covers on inhibiting oxidation and acid production, or to determine appropriate neutralization methods for mitigating the effects of acidic mine waters in open pits, or acidic discharge into the surrounding watershed (Zhu & Anderson 2002). Inverse mass balance models are typically used for establishing which geochemical reactions are likely to be responsible for specific changes observed in surface- or groundwater geochemistry. Even though mass balance modelling is not strictly based on either thermodynamics or reaction kinetics, it should be verified that all simulated reactions are thermodynamically and kinetically feasible, for example by using speciation modelling (see above). Inverse mass balance models can be used in mine environment investigations for determining amongst other things, rates of dissolution of critical mineral species and processes related to contamination of surface- and groundwater. Coupled reactive transport modelling is used for tracking and evaluating the dispersion of contaminant in solution, or changes in species concentration in the surrounding environment, or for studying migration of vapor phases through the system and consequent effects on for example, weathering processes. Reactive transport models can simulate both physical phenomena (such as advection, diffusion and dispersion) and geochemical processes (including degradation or (radioactive) decay of components, ion exchange, adsorption, redox reactions and mineral dissolution and precipitation). One of the fundamental issues in relation to the quality of the mining environment (particularly with respect to sulphide mines) is the potential for oxidation of sulphide minerals in tailings and waste rock facilities, and the consequent risk of acid mine drainage. Reactive transport models can be used to predict the composition of waters discharged from tailings and waste rock facilities, by simulating oxygen diffusion through tailings, and the effect of diffusion on sulphide oxidation and weathering (for example Wunderly et al. 1996, Lin and Qvarfort 1996). Transport models are also discussed further in relation to groundwater flow modelling, in the preceding section. Criteria for choosing the appropriate modelling approach depend on the nature of the problem and background data, and the specific objectives and issues to be addressed. In practice this may mean that several

147

diverse geochemical models are used either simultaneously or successively for testing different aspects of the problem. Within the context of mine closure investigations, in particular characterization of tailings and waste rock facilities, coupled reactive transport models are the most widely used, albeit in conjunction with other modelling techniques, in order to better constrain background parameters and input data. During the TEKES-funded project ”Environmental Techniques for the Extractive Industries”, geochemical modelling was used, for example, to evaluate water quality following filling of a former open pit (Kumpulainen 2005a, 2005b) and the long-term behaviour of waste rock facilities (Kumpulainen 2004, 2005c). These simulations involved the use of speciation- and reaction mechanism models and results have been published in several project reports (Kumpulainen 2004, 2005a, 2005b, 2005c). As with hydrogeological modelling, some geochemical modelling codes are freely available in the public domain, while others require purchasing a formal commercial license. On the other hand, a collaborative research group or consortium often undertakes development of coupled codes for a specific purpose, and therefore these codes might not be readily accessible to other users. Modelling software usually comprises both the processing code, as well as underlying databases for relevant parameters, including thermodynamic and kinetic variables and constants, and data on surface species. The most widely used geochemical modelling packages are MINTEQA2 (Allison et al. 1991) and PHREEQC (Parkhurst &Appelo 1999), both of which are suited to speciation modelling, capable of simulating redox-, ion exchange- and surface complexation reactions. PHREEQC is also capable of performing reaction mechanism models and inverse mass balance modelling, as well as one-dimensional reactive transport models. Additional software in common use for speciation, mass balance or reaction mechanism modelling include EQ3/6 (Wolery 1992), WATEQ4F (Ball and Nordstrom 1991), NETPATH (Plummer et al. 1994), SUPCTR92 (Johnson et al. 1992) and EQBRM (Anderson and Crerar 1993), with examples of coupled transport codes being MINTOX (Wunderly et al. 1996), PHREEQM (Glynn et al. 1991) and REACTRAN (Ortoleva et al. 1987). Summaries of geochemical software programs routinely used in mine environment studies, including an assessment of their relative strengths and weaknesses, has been

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given for example by Alpers & Nordstrom (1999) and Salmon (1999). Input parameters and background values for geochemical modelling vary according to the objectives and approach used. For the simplest types of speciation models, individual analyses of water chemistry and thermodynamic and kinetic data may be sufficient; the latter can usually be obtained directly from databases accompanying the software, although they may need to be supplemented by data published elsewhere or even by laboratory experiments. For studies related to mine closure, the analytical data for water chemistry should be as comprehensive and accurate as possible, including parameters such as pH, temperature, redox potential, alkalinity, electrical conductivity, as well as concentration of dissolved oxygen, dissolved anion and cation abundances, and additional data concerning redox pairs, for example proportions of ferric and ferrous iron. Depending on the purpose, modelling may also require, in addition to water chemistry and relevant thermodynamic and kinetic datasets, mineralogical composition and bulk chemistry data for the minerals in the system, and information on mineral species dissolution rates and specific surface area values. Coupled reactive transport modelling requires the most comprehensive range of input data, including variables affecting hydrogeological behaviour, in addition to the compositional parameters outlined above. Irrespective of which approach is adopted for modelling, the modeler always needs a clear understanding of the nature of the hydrogeochemical system under consideration, in addition to adequate input data and constraints. The outcome of geochemical modelling is contingent upon several factors, the most critical being the quality and quantity of input variables and the reliability of thermodynamic and kinetic databases. Input data may be deficient with respect to analytical precision, or the number of analyses available may be statistically invalid. The quality of surface water may for example, show significant variations due to seasonal fluctuations in precipitation; samples collected during rainy periods commonly tend to be more dilute than those collected during drier months. Moreover, measurements of water composition are particularly subject to analytical uncertainty. Where such uncertainty exists over data quality, the modelling process will inevitably become more reliant upon various assumptions, which must be taken into consideration when assessing the validity of model results.


References Allison, J.D., Brown, D.S. & Novo-Gradac, K.J. 1991. MINTEQA2/PRODERA2, a geochemical assessment model for environmental systems: version 3.0 user’s manual. U.S. Environmental Protection Agency Report EPA/600/3-91/021. Alpers, C.N. & Nordstrom, K. 1999. Geochemical modeling of water-rock interactions in mining environments. In: Plumlee, G.S. & Logsdon, M.J.: The environmental geochemistry of mineral deposits. Part A: Processes, Techniques, and Health Issues. Society of Economic Geologists, Inc. Reviews in Economic Geology, Volume 6 A., 289-323. Anderson, G.M. & Crerar, D.A. 1993. Thermodynamics in Geochemistry – The Equilibrium Model. New York, Oxford University Press. 588 s. Ball, J.W. & Nordstrom, D.K. 1991. User’s manual for WATEQ4F, with revised thermodynamic data base and test cases for calculating speciation of major, trace, and redox elements in natural waters. USGS Open-File Report 91-183. 189 p. Bear, J. & Verruijt A. 1994. Modeling groundwater flow flow and pollution, 3:rd ed., Riedel, Dordrecht, The Netherlands, 414 p. Bear, J. 1979. Hydraulics of groundwater. McGraw-Hill, New York, 569 p. Fontaine R.C., Davis, A. & Fennemore, G.G. 2003. The comprehensive realistic yearly pit transient infilling code (Cryptic): A novel pit lake analytical solution. Mine Water and the Environment 22, 187-193. Glynn, P.D. and Brown, J.G. 1996. Reactive transport modeling of acidic metal-contaminated ground water at a site with sparse spatial information. In: Lichtner, P.C., Steefel, C.I., and Oelkers, E.H., (eds.): Reactive Transport in Porous Media: Washington, D.C., Mineralogical Society of America, Reviews in Mineralogy, v. 34, p. 377-438. Haitjema, H.M. 1995. Analytic Element Modeling of Groundwater Flow. Academic Press, Inc. Hanna, T.M., Azrag, E.A. & Atkinson, L.C. 1994. Use of analytical solution for preliminary estimates of ground water in flow to a pit. Mining Engineering 46 (2), 149-152. Johnson, R.H. 1993. The physical and chemical hydrogeology of the Nickel Rim mine tailings, Sudbury, Ontario. M.Sc. Thesis, Department of Earth Sciences, University of Waterloo. Johnson, J.W., Oelkers, E.H. & Helgeson, H.C. 1992. SUPCRT: A software package for calculating the standard molal thermodynamic properties of minerals, gases, aqueous species, and reactions as functions of temperature and pressure. Computer & Geosciences 18, 899-947. Kruseman, G.P. & de Ridder, N.A. 1991. Analysis and evaluation of pumping test data. ILRI publication 47, (Reprint), Wageningen, 200 p. Kumpulainen, S. 2004. Hituran kaivoksen sivukivikasojen pitkäaikaiskäyttäytymisen mallintaminen. Osa 1. Pitkäaikaiskäyttäytymisen arvioinnissa käytettävät menetelmät. Kirjallisuusselvitys. Geologian tutkimuskeskus, julkaisematon tutkimusraportti. Espoo 27.9.2004. Kumpulainen, S. 2005a. Hituran kaivoksen avolouhoksen vedenlaadun mallintaminen. Osa 1. Avolouhoksen vedenlaatuun vaikuttavat tekijät ja arvioinnissa käytettävät menetelmät. Kirjallisuusselvitys. Geologian tutkimuskeskus, julkaisematon tutkimusraportti. Espoo 11.1.2005. 24 s. Kumpulainen, S. 2005b. Hituran kaivoksen avolouhoksen vedenlaadun mallintaminen. Osa 2. Veden laadun mallintaminen. Geologian tutkimuskeskus, julkaisematon tutkimusraportti. Espoo 7.5.2005. 25 s. Kumpulainen, S. 2005c. Hituran kaivoksen sivukivikasojen pitkäaikaiskäyttäytymisen mallintaminen. Osa 2. Mallintaminen. Geologian tutkimuskeskus. Julkaisematon tutkimusraportti 3.7.2005. 31 s. Lin, H.-C.J., Richards D.R., Talbot C.A., Yeh, G.-T., Cheng J.-R., Cheng, H.-P., Hua T., Jones, N.L. 2002. FEMWATER. Environmental Techniques for the Extractive Industries

A Three-Dimensional Finite Element Computer Model for Simulating Density-Dependent Flow and Transport in Variably Saturated Media. Version 3.0. Users Guide. Lin, Z. & Qvarfort, U. 1996. A study of the Lilla Bredsjön tailings impoundment in mid-Sweden – a comparison of observations with RATAP model simulations. Applied Geochemistry Vol. 11, 293-298. Lohman, S.W., 1972. Ground-Water Hydraulics. U.S. Geological Survey Professional Paper 708, 70 p. Marinelli F. & Niccoli W.L. 2000. Simple analytical equations for estimating ground water inflow to a mine pit. Ground Water 38 (2), 311-314. Marsily G., de 1986. Quantitative hydrogeology. Groundwater hydrology for engineers. Academic Press, London, 440 p. McDonald, M.G. & Harbauch, A.W. 1988. A Modular threedimensional finite-difference ground-water flow model. U.S. Geological Survey Techniques of Water-Resources Investigations, U.S. Geological Survey, Open-file Report 83-875, Book 6. A1, 586 s. Müller, M., Sames, D. & Mansel, H. 2003. PCGEOFIM – A Finite Volume Model for More? MODFLOW and More 2003: Understanding through Modeling. Conference in Golden, CO, USA, September 16 - 19.09.2003. Ogata, A. 1970. Theory of dispersion in a granular medium. U.S. Geological Survey Professional Paper 411-I. Ortoleva, P., Merino, E., Moore, C. H. & Chadam, J. 1987. Geochemical selforganization I: feedback mechanism and modelling approach. American Journal of Science 287, 979-1007. Parkhurst, D.L. & Appelo, A.A.J. 1999. User’s guide to PHREEQC (version 2) – A computer program for speciation, batch-reaction, one dimensional transport, and inverse geochemical modeling. U.S. Geological Survey, Water Resources Investigations, Report 99-4259. 312 s. Plummer, L.N., Prestemon, E.C., & Parkhurst, D.L. 1994. An Interactive Code (NETPATH) for Modeling NET Geochemical Reactions along a flow PATH. (Version 2.0). U.S. Geological Survey, Water Resources Investigations, Report 94-4169. 130 s. Pruess, K. 1991. TOUGH2 – A general purpose numerical simalator for multiphase fluid and heat flow. LBL-29499, UC-251, Berkely, California. Salmon, S.U.J. 1999. Mimi – Overview of models for biogeochemical modeling of acid mine drainage. MiMi report 4/1999. ISBN 91-89350-10-3. 37 s. Strack, O.D.L. 1989. Groundwater Mechanics. Prentice Hall. Sudicky, E.A. & McLaren, R.G. 1992. The Laplace transform Galerkin technique for large-scale simulation of mass transport in discretely fractured porous formations, Water Resour. Research, 28 (2), 499-514. Therrien, R., Sudicky, E., McLaren, R.G. 1999. Users Guide for NP 3.49 A preprosessor for FRAC3DVS. Three-dimensional, Saturated-Unsaturated Groundwater Flow and Chain-Decay Solute Transport in Porous or Discretely-Fractured Porous Formations. Toran, L. & Bradbury, K.R. 1988. Groundwater flow model of drawdown and recovery near an underground mine. Ground Water, vol. 26, 724-733. Wolery, T.J. 1992. EQ3/EQ6, A software package for geochemical modeling aqueous systems: Package overview and installation guide (Version 7.0). Lawrence Livermore National Laboratory. Wunderly, M.D., Blowes, D.W., Frind, E.O. & Ptacek, C.J. 1996. Sulfide mineral oxidation and subsequent reactive transport of oxidation products in mine tailings impoundments: A numerical model. Water Resources Research, Vol. 32 (10), 3173-3187. Zhu, C. & Anderson, G. 2002. Environmental applications of Geochemical Modeling. Cambridge University Press. 284 s.

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APPENDIX 11. INVESTIGATION OF CONTAMINATED SOIL AND MONITORING REMEDIATION PROGRESS When mining ceases, it is necessary to assess whether mining activities have had any detrimental effect on soils, surface waters or groundwaters. If contamination has occurred, then remediation measures must be planned and implemented, using the following process as a guideline (see also Alanko and Järvinen 2001, SGY 2002, Öljyalan palvelukeskus 2002): 1) Preliminary investigations • Evaluation of general conditions and background information ◦ State of environment prior to commencement of mining ◦ Documentation of all activities during mining operations ◦ Documentation of any accidents or environmental incidents during mining ◦ Documentation of any previous investigations into contamination and ensuing remediation procedures ◦ Preliminary evaluation of contaminants present at the site and their likely properties and behaviour • Evaluation of available planning data and maps ◦ Precise location of activities that may potentially have impact on soils or surficial and ground waters • Collation of existing geological, geochemical and hydrogeological data ◦ Geochemical baselines and properties of surficial materials ◦ Groundwater flow paths and surface water drainage systems ◦ Results of environmental monitoring studies 2) Site investigation plan for contaminated areas • Preliminary plan of sampling network, with suggested density of observation points and locations on maps • Sampling technique(s) • Recommended depth of sampling sites and proposed sampling depths • Number and volume of samples required • Sample selection criteria, numbers and analytical requirements, for both in-situ and laboratory investigations • Sample preparation techniques • Timetables and schedules • Occupational health and safety issues • Relevant regional environmental authorities to be informed of the sampling and investigations, including submission of a detailed plan of research activities for assessment and comment 3) Sampling procedures • Sampling is to be carried out in accordance with research plan submitted to the environmental authorities • Details of sampling are to be carefully documented in a standard approved manner • A report is prepared based on sampling and results of analyses, and a copy should be sent to the relevant environmental authorities. The report should include an evaluation of the status of contamination

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4) Site-specific risk assessment (the scheme illustrates the different phases that are recommended to carry out while site is recognized contaminated) • If the site investigation has revealed that soil is contaminated, a basic risk assessment should be carried out • Basic risk assessment includes assessment of ecological and health risks related to land use and environmental conditions in the area. Basic risk assessment should also establish whether soil contamination significantly impairs the quality or amenity of the site or causes comparable violation of public or private good • Assessment of risks is based on detailed site description: distribution of contaminants at the site (source), dispersion of contaminants (pathway), exposure routes, identifying the exposed elements • Site description includes assessment of all potentially hazardous materials in the studied area, including concentrations in relation to legally prescribed threshold and guideline values, dispersal pathways i.e. migration (as a reflection of local environmental conditions), implications for current and future land use activities and potential susceptibility to short-term and longer term ecological or health risks • During the first stages of assessment, the acceptability of detected risks is mainly based on the enacted threshold and guideline values • More comprehensive risk assessment specifies the general status of the site and identified risks, focusing on assessment of those risk factors which could not be acceptably defined through basic risk assessment • More comprehensive risk assessment includes description of both identified risks and uncertainty analysis • Regional environmental authorities make the final decisions concerning the need for site remediation or further investigations based on risk assessment oriented report of investigations 5) General plan for remediation of contaminated soil sites • Drafted on the basis of results of investigations and sitespecific risk assessment • Assessment of remediation requirements and definition of objectives and determination of optimum remedial methods (best practice procedures using best available technologies (BAT)) • Plan for remediation of contaminated soil site to be submitted to regional environmental authorities 6) Remediation of contaminated soil • Before site remediation can commence, it is obligatory to either inform the relevant environmental authorities or in some cases obtain a formal environmental permit • Thorough written documentation of the site remediation program is required, describing each stage of implementation • When the remediation project is complete, a final report is prepared, with an assessment of the effectiveness of the program against objectives and performance indicators, as well as recommendations relating to possible restrictions on future land use and ongoing site monitoring responsibilities • The final report is to be submitted to the appropriate regional environmental authorities


Identification of the need for assessment

History and site information

Are threshold and background values exceeded?

No

Yes

Yes SOIL IS NOT CONTAMINATED

ASSESSMENT OF SOIL CONTAMINATION IS NEEDED

Can guideline values and other generic reference values be applied?

No

Yes Are guideline values and other reference values exceeded?

No

Yes

Risk description

Other No issues to consider related to EPA 7§? Yes

Basic assessment

Site description

Risk description

Objectives and delineation of assessment

Health risks

Transportation risks

Ecological risks

Risk description and uncertainty analysis

Are risks acceptable?

No

More detailed assessment

Site investigations to attain necessary information for risk assessment

No

Are there other potential hazards?

Yes

SOIL IS CONTAMINATED AND RISK MANAGEMENT IS NEEDED

SITE IS NOT CONTAMINATED, NO NEED FOR RISK MANAGEMENT, LAND USE RESTRICTIONS MAY BE NEEDED

Figure 1. The assessment of soil contamination and the need for remediation (Ympäristöministeriö 2007)

References Alanko, K. & Järvinen, K. 2001. Pilaantuneen maa-alueen kunnostuksen yleissuunnitelma. Ympäristöopas 83, Suomen ympäristökeskus. 77 s. SGY 2002. Suomen geoteknillinen yhdistys ry. Ympäristögeotekninen näytteenotto-opas: maa-, huokoskaasu- ja pohjavesinäytteet, moniste. 37 s. + 7 liitettä.


Öljyalan palvelukeskus Oy 2002. Öljyllä pilaantuneen maaalueen kunnostaminen. Opas kunnostushankkeen toteuttamiseksi. Moniste. 106 s. Ympäristöministeriö 2007. Maaperän pilaantuneisuuden ja puhdistustarpeen arviointi. Ympäristöhallinnon ohjeita 2/2007. Ympäristönsuojeluosasto, Ympäristöministeriö. 210 s, 17 liitettä.

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APPENDIX 12. METHODS FOR TREATMENT OF MINE WATERS

Detailed descriptions of selected currently available techniques for treating mine waters are given below:

Neutralization of waste waters Chemical treatment of waste waters at the mine site usually involves addition of alkaline compounds to neutralize the typically acidic compositions of mineinfluenced waters (Ledin & Pedersen 1996). The most commonly used compounds are carbonate in the form of calcite (CaCO3), lime (CaO) (Ledin & Pedersen 1996), sodium hydroxide (NaOH), sodium bicarbonate (Na2CO3) (Lenter et al. 2002) and magnesium oxide (MgO) (Gazea et al. 1996). As a result of addition of these alkaline materials, water pH increases and dissolved metals precipitate as hydroxides or carbonates. Under near-neutral pH conditions, the precipitates remain relatively stable and insoluble (MEND 1994). Neutralization treatment is suitable for all types of acidic mine-influenced waters, irrespective of their total metal concentrations or acidity (MEND 1994). Nevertheless removal of metalliferous sludge precipitated during this treatment process (Ziemkiewicz et al. 2003) and appropriate disposal may be problematic, due to the elevated concentrations of potentially toxic metals (MEND 1994). Moreover, operating and monitoring costs of these treatment methods can be very expensive (MEND 1994, Gazea et al. 1996).

Anoxic limestone drainage systems (ALD) Anoxic limestone drains (ALD, contrasting with open limestone drains = OLD) represent a passive remediation technique whereby the acidity of mine waters is reduced by directing the non-aerated effluent stream through calcium-bearing material (PIRAMID Consortium 2003). The limestone drainage system consists of a buried trenches containing single-size crushed limestone, saturated with water such that mine waters directed through the drainage system are excluded from oxygen (MEND 1996). When in contact with acid mine drainage, carbonate in the drain dissolves and hence increases the water pH, promotes bicarbonate-alkalinity and enhances the buffering capacity of the water (PIRAMID Consortium 2003). Conversely, an increase in pH promotes precipitation of metallic compounds (MEND 1994). Where they operate to maximum efficiency, anoxic limestone drains can produce water of good quality (Gazea et al. 1995). Moreover, ALD systems can be expected to be effective for considerable

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lengths of time (MEND 1996). Nevertheless, drainage systems are susceptible to loss of efficiency due to lowering of permeability, caused by formation of iron- and aluminum hydroxides (Fe(OH)3 and Al(OH)3). Ferric hydroxide armor the limestone whereas aluminum hydroxides plug the drain flow paths (Gazea et al. 1996, Ziemkiewicz et al. 2003). The method is best suited to slightly acidic mine waters (Ziemkiewicz et al. 2003), with dissolved oxygen concentrations less than 1 mg/L (MEND 1996), ferric iron and aluminum concentrations less than 2 mg/L (PIRAMID Consortium 2003, Gazea et al. 1996) and sulphate concentrations below 2000 mg/L (Hedin et al. 1994, MEND 1996). Reducing and alkalinity producing systems (RAPS) function in effectively the same way as anoxic limestone drains (ALD), but with the additional feature that waters are firstly channeled through a compost bed. A distinct advantage of this approach over the conventional anoxic limestone drain method is that water chemistry is modified such that metal hydroxides are unable to form and flocculate on carbonate particles, which thus allows the limestone drain to remain operational for longer period of time. The RAPS method can therefore be used where acidic mine waters contain elevated concentrations of ferric iron, aluminum and dissolved oxygen (PIRAMID Consortium 2003).

Constructed wetlands Wetlands represent an ecological treatment method whereby varieties of chemical, physical and biological processes interact resulting in significant changes in the water chemistry (MEND 1996). Wetlands can be divided into two broad categories, namely aerobic and anaerobic. Aerobic wetlands are designed to maximize the opportunities for promoting oxidation reactions (MEND 1996), as a result of which metals precipitate from solution primarily as hydroxides, oxyhydroxides and oxides, accumulating in wetland sediment (Gazea et al. 1996, Ziemkiewicz et al. 2003). In contrast, anaerobic wetlands rely on the lack of oxygen and maintaining reducing conditions, so that neutralization of acidic effluent is achieved by generating alkalinity through a combined action of bacterial sulphate reduction and limestone dissolution (Gazea et al. 1996). To enhance this method of treatment, an organic substrate (such as compost, hay, manure, peat, woodchips or sawdust) is added, to promote bacterial activity and to ensure reducing conditions (Gazea et al. 1996, Pinto et al. 2001). Aerobic wetland treatment Mine Closure Handbook P. M. Heikkinen, P. Noras and R. Salminen (eds.)

is mainly applicable to the remediation of net alkaline mine waters, particularly those with elevated iron concentrations (PIRAMID Consortium 2003), while anaerobic wetlands are more appropriate for treatment of net acidic mine waters (Gusek et al. 1994, Ziemkiewicz et al. 2003).

ment. However, the shaft or pit must be deep enough, such that temperature differences between surface and deeper levels do not permit convective overturn and mixing, thereby ensuring that conditions at the bottom of the mine remain anoxic (Mustikkamäki 2000).

Permeable reactive barriers and leach beds Bioreactors Mine waters containing sulphate and metallic ions can be effectively treated with conventional bioreactors designed for methanogenic treatment of wastewaters (Hulshoff Pol et al. 1998). The effectiveness of bioreactors relies largely on the activity of sulphate-reducing bacteria (Gusek et al. 1994, Silva et al. 2002, Jong & Parry 2003), which can be further facilitated by the addition of appropriate electron donor, carbon source and nutrients (Hulshoff Pol et al. 1998, Zaluski et al. 2003). As a result, sulphate is reduced and metals precipitate as sulphides (Christensen et al. 1996, de Lima et al. 1996, Kaksonen et al. 2003). Bioreactors offer advantages in terms of their modest space requirements, and their ease of construction and operation (MEND 1996). However, overall expenses may be greater than for other microbiological remediation techniques because they require constant monitoring and maintenance (Gibert et al. 2003). Flooded open pits and mine shafts can also be used as large bioreactors (Riekkola & Mustikkamäki 1997). Bacterial growth and metabolism are stimulated directly in the contaminated water body and the mine itself is used as a sedimentation basin for metal sulphide sludge formed by precipitation. In order to promote bacterial growth, source of organic substrate and nutrients is added into the open pit or mine shaft (RiekkolaVanhanen 1999, Riekkola-Vanhanen & Mustikkamäki 1997). This approach makes it possible to control the chemistry of waters discharging from the pits and shafts before their release into surrounding environ-


Permeable reactive barriers (PRBs) installed in situ in the groundwater flow path can be used to remove contaminants from mine-impacted groundwater. Contaminants are removed by trapping them chemically in a suitable reactive media, or as a result of bacterial sulphate reduction (Waybrant et al. 1998). Processes which can be effective in reducing concentrations of contaminants from solution or suspension, or in removing them entirely, include adsorption, precipitation, oxidation, reduction, chemical or microbiological transformations or combination of these processes (Puls et al. 1999). Leach beds or filtration beds operate in a similar manner as PRBs, although the beds can also be installed in surface water drainage channels, for instance in the water channels within the mine area (Riekkola-Vanhanen 1999). The most critical aspect affecting functionality of both permeable reactive barriers and filtration beds is the composition of the reactive material (Waybrant et al. 1998). In addition to an appropriate substrate and carbon source (Waybrant et al. 1998), the PRB or filtration bed requires a source of bacteria for cultivation of an appropriate strain of sulphate reducing bacteria (Christensen et al. 1996, Moosa et al. 2002, Cocos et al. 2002) together with additional chemicals and nutrients (Herbert et al. 2000, Cocos et al. 2002, Barnes et al. 1991, Benner et al. 1997, Madigan et al. 2000) to further promote bacterial activity and hence efficiency of the treatment process. The reactive material must be sufficiently permeable to ensure that the groundwater flows through the reactive system at the desired flow rate (Benner et al. 1997).

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References Barnes, L.J., Sherren, J., Janssen, F.J., Scheeren, P.J.H., Versteegh, J.H. & Koch, R.O. 1991. Simultaneous microbial removal of sulphate and heavy metals from waste water. EMC, Belgium, pp.391–401. Benner, S.G., Blowes, D.W. & Ptacek, C.J. 1997. A full-scale porous reactive wall for prevention of acid mine drainage. Ground Water Monitoring & Remediation, Vol. 17, Issue 4, pp. 99–107. Christensen, B., Laake, M. & Lien, T. 1996. Treatment of acid mine water by sulfate-reducing bacteria; results from a bench scale experiment. Water Research. Vol. 30, No 7, pp.1617–1624. Cocos, I.A., Zagury, G.J., Clément, B. & Samson, R. 2002. Multiple factor design for reactive mixture selection for use in reactive walls in mine drainage treatment. Water Research 32, pp. 167–177. Gazea, B., Adam, K. & Kontopoulos, A. 1996. A review of passive systems for the treatment of acid mine drainage. Minerals Engineering. Vol. 9, No 1, pp. 23–42. Gibert, O., de Pablo, J., Cortina, J.L. &Ayora, C. 2003. Evaluation of municipal compost/limestone/iron mixtures as filling material for permeable reactive barriers for in-situ acid mine drainage treatment. Journal of Chemical Technology and Biotechnology, Vol. 78, pp. 489–496. Gusek, J.J., Gormley, J.T. & Scheetz, J.W. 1994. Design and construction aspects of pilot-scale passive treatment systems for acid rock drainage at metal mines. Hydrometallurgy ’94, Cambridge, England, July 11–15, 1994. The Institution of Mining and Metallurgy and the Society of Chemical Industry, pp.777–793. Hedin, R.S., Narin, R.W. & Kleinmann, R.L.P. 1994. Passive treatment of coal mine drainage. Bureau of Mines Information Circular. United States Department of the Interior. 35 p. Herbert, R.B. Jr., Benner, S.G. & Blowes, D.W. 2000. Solid phase iron-sulfur geochemistry of a reactive barrier for treatment of mine drainage. Applied Geochemistry 15, pp. 1331–1343. Hulshoff Pol, L.W., Lens, P.N.L., Stams, A.J.M. & Lettinga, G. 1998. Anaerobic treatment of sulphate-rich wastewaters. Biodegradation 9, pp. 213–224. Jong, T. & Parry, D.L. 2003. Removal of sulfate and heavy metals by sulfate reducing bacteria in short-term bench scale upflow anaerobic packed bed reactor runs. Water Research 37, pp. 3379–3389. Kaksonen, A.H., Plumb, J.J., Franzmann, P.D. & Puhakka, J.A. 2003. Simple organic electron donors support diverse sulfatereducing communities in fluidized-bed reactors treating acidic metal- and sulfate-containing wastewater. FEMS Microbiology Ecology 1610, pp. 1–11. Article in press. Ledin, M. & Pedersen, K. 1996. The environmental impacts of mine wastes – Roles of micro-organisms and their significance in treatment of mine wastes. Earth-Science Reviews 41, pp. 67–108. Lenter, C.M., McDonald, L.M. Jr., Skousen, J.G. & Ziemkiewicz, P.F. 2002. The effects of sulfate on the physical and chemical properties of actively treated acid mine drainage floc. Mine Water and the environment 21, pp. 114–120. de Lima, A.C.F., Silva, M.M., Leite, S.G.F., Gonçalves, M.M.M. & Granato, M. 1996. Anaerobic sulphate-reducing microbial process using UASB reactor for heavy metals decontamination. In Sánchez M.A, Vergara F & Castro S.H (eds.). Clean Technology for the mining industry, University of Concepción, Concepción-Chile, pp. 141–152.

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Madigan, M.T., Martinko, J.M. & Parker, J. 2000. Brock Biology of Microorganisms. 9th Edition. Prentice Hall, Inc., New Jersey, USA. 991 p. MEND 1994. Acid Mine Drainage-Status of Chemical Treatment and Sludge Management Practices. Mine Environment Neutral Drainage Program. MEND Report 3.32.1. June 1994. 62 p. MEND 1996. Review of passive systems for treatment of acid mine drainage. Mine Environment Neutral Drainage Program. MEND Report 3.14.1. May 1996. 72 p. Moosa, S., Nemati, M. &Harrison, S.T.L. 2002. A kinetic study on anaerobic reduction of sulphate, Part I: Effect of sulphate concentration. Chemical Engineering Science 57, pp. 2773–2780. Mustikkamäki, U.-P. 2000. Metallipitoisten vesien biologisesta käsittelystä Outokummun kaivoksilla. Vuoriteollisuus 1, pp. 44–47. Pinto, A.P., Wildeman, T.R.. & Gusek, J.J. 2001. Remediation properties of materials to treat acid mine drainage water at gold mine operation in Brazil. The 2001 National Meeting of the American Society of Surface Mining and Reclamation, Albuquerque, New Mexico, June 3–7, 2001. 7 p. PIRAMID Consortium 2003. Engineering guidelines for the passive remediation of acidic and/or metalliferous mine drainage and similar wastewaters. European Commission 5th Framework RTD Project no. EVK1-CT-1999-000021 ”Passive insitu remediation of acidic mine / industrial drainage” (PIRAMID). University of Newcastle Upon Tyne, Newcastle Upon Tyne UK. 166pp. http://www.piramid.org/PIRAMID%20 Guidelines%20v1.0.pdf Puls, R.W., Blowes, D.W. & Gillham, R.W. 1999. Long-term performance monitoring for a permeable reactive barrier at the U.S Coast Guard Support Center, Elizabeth City, North Carolina. Journal of Hazardous Materials 68, pp. 109–124. Riekkola-Vanhanen, M. 1999. In situ bioreclamation of acid mine drainage. In: Kuusisto, S., Isoaho, S. & Puhakka, J. (eds.). Fourth Finnish Conference of Environmental Sciences. Tampere, Finland, May 21–22, 1999. Environmental Science, Technology and Policy, pp. 22–25. Riekkola-Vanhanen, M. & Mustikkamäki, U.-P. 1997. In situ bioreclamation of acid mine drainage by sulphate reducing bacteria in an open pit mine. International Biohydrometallurgy Symposium IBS97 Biomine 97 – Biotechnology Comes of Age. Sydney, Australia, August 4–6. 1997. Silva, A.J., Varesche, M.B., Foresti, E. & Zaiat, M. 2002. Sulphate removal from industrial wastewater using packed-bed anaerobic reactor. Process Biochemistry 37, pp. 927–935. Waybrant, K.R., Blowes, D.W. & Ptacek, C.J. 1998. Selection of reactive mixtures for use in permeable reactive walls for treatment of mine drainage. Environmental Science&Technology 32, pp. 1972–1979. Zaluski, M.H., Trudnowski, J.M., Harrington-Baker, M.A & Bless, D.R. 2003. Post-mortem findings on the performance of engineering SRB field-bioreactors for acid mine drainage control. 6th International Conference on Acid Rock Drainage, Cairns, Australia, July 12–18, 2003, pp. 845–853. Ziemkiewicz, P.F., Skousen, J.G. & Simmons, J. 2003. Longterm performance of passive acid mine drainage treatment systems. Mine Water and the Environment 22, pp. 118–129.


APPENDIX 13. EXAMPLES OF TAILINGS COVER APPLICATIONS IN REMEDIATION OF MINE SITES IN THE NORDIC COUNTRIES

Dry tailings covers have been used in mine site remediation at several locations in Finland, as in other Nordic countries, including the Enonkoski and Keretti mines in Finland and the Viscaria mine in Sweden. Several detailed descriptions of procedures for dry tailings covers and their implementation are presented below: • The Enonkoski nickel mine, which ceased operations in 1985, is located in the Enonkoski municipality, north of Savonlinna. The tailings at Enonkoski are covered with a layer of till about 50 cm thick. The area was sown with a so-called TVL seed-mix and fertilizer has also been added to the area. Seepage waters are directed into two separate wetland areas for treatment. • The Keretti Cu-Co-Zn-Ni mine was the most significant ore deposit in the Outokumpu district, until production ceased in 1989. Tailings deposits have been covered with about 20 cm of gravel, overlain by some 10 cm of peat mixed with sand at a ratio of 20:1. Vegetation cover was initially established by sowing a so-called TVL seed mixture, with addition of fertilizer. Seepage waters are channeled through two wetlands for treatment. • The Viscaria sulphide deposit in northern Sweden primarily produced copper. The tailings area was covered with a 3-5 cm layer of fine sludge obtained from the waste water treatment plant. The area was vegetated using a so-called TVL seed-mix, supplemented by fertilizer. Owing to the relatively high neutralization capacity of the tailings (due to low sulphide content and high calcite abundance), there has been no significant acid production at the site. The incentive for covering the tailings was thus more aesthetic, in terms of landscaping and re-establishing vegetation cover, such that the endemic dwarf birch would progressively recolonize the area. In order to arrest potential erosion caused by extreme rainfall events and flooding, a system of drainage furrows and channels has subsequently been constructed using a combination of till and geotextile lining material (Naturvårdsverket 2002). • The Kristineberg mine in Sweden has been in continuous operation since 1940. There are five separate tailings impoundments at the site, containing tailings material derived from a total of ten different processing and beneficiation techniques (Naturvårdsverket 2002). The first attempts at rehabilitation of the oldest tailings area (dating from the early 1950’s) involved planting grass directly on the tailings. During 1996, impoundments 1 and 2, and parts of impoundments 3 and 4, were treated by a combination of covering the tailings with till, raising the water table and planting vegetation, or submerging tailings beneath water. In areas where the water table is near the ground surface, a protective layer consisting of till, about

a meter in thickness, was added. Where depth to the water table was greater, the corresponding layer thickness was 1.5 meters, which was spread over an initial layer of finer-grained clayey till 0.3 meters thick. Prior to this, the tailings were also treated with lime. Of those areas that were submerged by construction of raised dams, the aim was to maintain a water depth of about one meter. Site monitoring has revealed that pervasive oxidation penetrates to a depth of about 50 cm beneath the surface of the tailings. Arsenic and copper show some enrichment immediately beneath the based of the oxidized layer. As a result of raising the water table, leaching of metals enriched beneath the oxidized layer has subsequently occurred, thus increasing the concentration of metal species in pore waters. • Galgbergsmagasinet, Sweden. The tailings area was covered with a composite material one meter in thickness, comprising a mixture of fiber pulp and fly-ash, which was then compacted as two separate layers and covered by a 0.5 meter thick layer of wood processing residue and coarsegrained till. Laboratory testing of the material revealed a permeability of 1.5 for all earthen dam and embankment structures.

Treatment with lime, partial covering with water, sludge removal by pumping as slurry, immediate planting of vegetation whenever tailings embankment is raised

Recycling of processing waste waters and capture of tailings drainage waters for treatment. Precipitation of metals as hydroxides in tailings drainage system, return water to concentrating plant. Ensure that controlled release of mine waters is diluted with natural water at a ratio of 1:500; regulation of waste water pH if necessary

Groundwater flow through aquifer in (interlobate) esker passing through tailings area is arrested by impervious clay barriers. Effectiveness evident in lowered sulphate abundances. Lining of drainage channels.

Existing risk abatement and mitigation strategies

Adverse impacts on surrounding waters are only likely if exceptional circumstances (intense rainfall, rapid snowmelt) require unscheduled release of waste waters

Most sulphate in pore waters is derived from sulfuric acid used in processing, while chloride is mainly derived from ore. Nitrogen originates from explosives

Comments


157

Mine (Underground and open pit operations)

Waste rock storage facilities

Discharge into groundwaters (explosives residues, sulphide oxidation, mining activity)

Other safety issues • Unauthorized vehicular or pedestrian entry Noise Impact on landscape Wastes and treatment • Miscellaneous waste mixed with waste rocks 3

2

2

2

3

3

2 1

2 3

1 2

1

1

1 4

1

3

3

2 2

4 3

5

2 1

1

3 1 1

3 3

1

Waste generation and treatment

Discharge into groundwaters • Oxidation • Explosives residues Discharge into surface waters • Discharge into drainage channels • Discharge from mine drainage systems and waste facilities into surrounding agricultural drainage network • Further discharge via agricultural drainage network into rivers and streams Changes in hydrological balance Atmospheric emissions • Dust • Gaseous emissions (from sulphide oxidation) Stability issues

4 1 4

Other safety risks • Unauthorized access to tailings area Noise Impact on landscape

Minimal

Minimal

Negligible Moderate

Significant

Minimal

Minimal Minimal

Negligible

Minimal

Moderate Minimal

Minimal Minimal

Negligible

Moderate Negligible Minimal

Water in open pit ultimately drains into underground mine workings. Deterioration of bedrock groundwater quality due to infiltration of waters affected by mining activities (explosives residue and chemicals, vehicular emissions) and sulphide weathering

Modification of original landscape Waste rock storage facilities also contain waste derived from previous site infrastructure

Injury from falling, burial by rockfall or scree, illegal dumping of unauthorized waste

Rockfalls

Accumulation of water in open pit dominantly from meteoric precipitation, which infiltrate into underground workings, where pumping returns water to surface. Pumping operations induce groundwater downdraw and flow towards mine

Waste no longer accumulated at waste rock facility and has been covered with rock and topsoil

Terracing of piles to stabilize slopes, in accordance with geotechnical assessments of maximum angle of repose and load-bearing capacity of substrate Restriction of vehicular access by placement of rock barriers and dismantling drainpipes at culvert crossings

Establishment and regeneration of native vegetation

Buffer zones between waste heaps and open drainage systems (locally); waters directed through settling and clarification ponds

Deterioration of surface water quality and restrictions on use. Impact on biota. Metal transport by water and infiltration into soil.

Unlikely for highly permeable materials Extremely small amounts of dust (generated during crushing) coating rock surfaces in waste rock piles

Siting of waste rock storage facilities on low-permeability substrate, remote from exploited groundwater aquifers

Vegetation planting programs on embankments, and natural regeneration

Locked gates and barriers preventing access by road, and warning signs

Deterioration of groundwater quality and restrictions on use, possible adverse effect on soil quality.

Traffic very sporadic Modification to original landscape

Becoming trapped in mud, sinking or drowning

158


Transport and crushing of ore

1 3

2 5

4 4

4 4

Atmospheric emissions • Airborne particles • Gaseous emissions

Stability issues • Open pit • Underground workings

Discharge into surface waters and ground waters • Contaminated soil • Spillage and leakage of oil lubricants and fuel

Effect on landscape

Noise and vibration

Other safety issues • Access to open pit area by unauthorized persons • Access to underground mine areas by unauthorized persons

2

3

4 3

2

2 3

1

2

4

1

4

3

3

2 2

2 2

2

4

Discharge to surface waters from mine pumping • Discharge into waste facility drainage systems • Discharge into surrounding agricultural drainage systems • Discharge into rivers and streams Changes in hydrological balance

Moderate Moderate

Negligible

Moderate

Minimal

Moderate

Moderate Moderate

Moderate Moderate

Negligible Significant

Minimal

Moderate

Metal migration into surface waters and ground waters

Local modification of original landscape

Noise from mine vehicles, blasting operations, and from air ventilation system. Vibration from blasting operations.

Risk of falling and injury. Risk of becoming lost, dangers from mining equipment or explosives

Collapse of pit walls. Underground failure and collapse, which also affects stability and subsidence in open pit and surroundings

Particulate emissions from mining machinery, explosives and loading operations. Metal content and susceptibility to acidification means that dust can adversely affect quality of water pumped out of mine. Exhaust emissions from mining machinery and vehicles, residual gases from blasting operations, impact on health of miners

Drying of wells

Deterioration of surface water quality, restrictions on use; effects on biota. Dispersal of metals via water infiltration into surrounding surficial materials, with possible restrictions on subsequent extraction or land use activities

Clay-rich surficial sediments inhibit infiltration of contaminated waters. Pre-emptive servicing of machinery. Automated monitoring of oil supply

Prevention of unauthorized entry to open pit and surrounding safety buffer zone. Backfilling of open pit with waste rock. Strengthening of underground tunnels and galleries with rockbolting, meshing and shotcrete Access to mine area primarily through security staff at mine entrance. Underground access only in company of authorized personnel; vehicular traffic restricted to defined, remotely monitored routes, while blasting, loading and transport of ore is suspended Ventilation systems and vehicles equipped with sound dampers. Strict scheduling of blasting activities. Pit walls and waste heaps and embankments act as barriers for noise abatement. Bedrock and overburden tend to dampen noises and vibrations generated during underground mining Revegetation around edges of open pit

Connection to municipal reticulated water supply Periodic monitoring for presence of carbon monoxide and abundance of airborne particulate emissions. Vehicles exceeding emissions limits to be excluded from mine area

Water channeled through settling and clarification ponds before discharge into surrounding water catchment.Oil containment booms at settling pond outflow sites.

Significant issue for mine workers, effects outside mine less significant

Dust release via ventilation system exhaust outlets throughout the mine area. Dust settles extensively throughout the open pit area (over 40 ha); pit walls and floor contain sulphide minerals.


159

Storage and transport of concentrate

Concentrator plant

• • •

• 4 3 3

4

4

•

1 3 1

3

2

5

4

Oxidation of concentrate stored in stockpiles Dispersal of wind-borne concentrate dust from loading site Loss of control of loaded truck Other road accidents Noise and dust generation during loading and transport

1

3

4

2

2

4

2

3

2

4

1

Other safety risks • Sulfuric acid leaks from feeder pipes • Leakage of other reagents from pipes or (short-term) overflow from storage tanks • Fire

Atmospheric emissions • Particulate emissions • Gaseous emissions ◦ Generation of hydrogen sulphide from excess addition of sulfuric acid ◦ Formation of carbon disulfide from reaction between xanthates and acids

4

Impact on landscape

3 4 2

3 2

4 4

3 3 4

1

4

Other safety risks • Conveyor belt or vehicle fire • Traffic accidents Noise

Atmospheric emissions • Dust generated during road transport • Dust generated at crushing facilities • Generation of dust from drying rock surfaces in temporary storage sites and around crushing plant

Minimal Moderate Minimal

Moderate

Moderate

Significant

Minimal

Minimal

Moderate

Moderate

Moderate

Minimal

Moderate Moderate Moderate

Moderate Moderate

Minimal

Migration of metals into soil, and surface and groundwater. Dispersal outside asphalted areas causes contamination of soils and runoff into surface drainage systems. Contamination of soil, surface waters, and groundwater. Mass of full load = 40 t. Risk of human injury < 1000 loads per year

Structural corrosion and human casualties. Leaks are transient and small. Toxic gases released during combustion of cables, plastic pipes and tubes, rubber, lubricants, and flotation frothing agents. Water and extinguishing agents used for firefighting cause contamination of soil, surface waters and ground waters

Dust transported by ventilation of exhaust systems and settles on asphalted areas and other nearby locations. Risk of worker respiratory problems and poisoning

Areas prone to dust generation, such as crushing mill feeder, enclosed, dust collected and extracted with hose filters. Automated pH regulation to ensure controlled release of sulfuric acid in concentration process. Dilution of acid with water prior to feeding for processing. Separate storage and addition of xanthates and acids to processing system. Xanthate solutions prepared in separate location away from acid reagents Periodic inspection of feeder pipes. Leaked material is collected in drains and piped to waste pumps and tailings impoundment. Fire safety regulations and conduct code; compartments for fire containment and isolation; regular fire safety inspections; emergency response plan. Smoke and gas detectors in offices and buildings with electrical fittings and equipment Concentrate stored primarily under cover. Stockpile storage areas paved with asphalt. Main storage area floored by concrete. Inclined surfaces of storage area to collect rainwater into milling process. Immediate removal of concentrate and any associated surface soil and transport to mine. Transported loads to be covered.

Soundproofing and enclosing of dust extraction systems. Confinement of activities to within stockpile areas or areas enclosed by sound barriers, use of percussion drills restricted to hours between 08:00-16:00

Noise from mining activities and traffic; Noise from percussion drilling

Industrial infrastructure

Salting and wetting of ore haulage roads and temporary stockpiles. Enclosing of conveyor belts, roofing over stockpiles and confining main dust generation phase to interior of crushing facility. Centralized ventilation and dust removal and siltation. Watering of ore during crushing process in summer months Fire safety regulations and emergency procedures protocol. Clear traffic signage

Contamination of road verges and exposed ground in proximity to the crushing mill. Surface contamination further away from airborne dust. Oxidation of sulphide-bearing dust and transport via melt waters and runoff into adjoining drainage systems. Contamination of soil, air, surface waters and groundwater Human casualties, generation of harmful smoke. Workers and visitors

160


2

3

•

Severity of consequences Extremely severe Severe Moderate Minimal Negligible

1

1 Minimal

Minimal

Negligible Negligible

Negligible to moderate Minimal to moderate Moderate

Negligible to significant

Unacceptable risk Significant risk Moderate risk Minimal risk Negligible risk

Increase in chemical oxygen demand and release of nutrients Metalliferous hazardous waste generated (200t dry matter/a) is combined with concentrate, treated water recycled back into concentrator processing system, thus improving the overall rate for waste water recycling

Collection skips Collection bins and skips

Leakage of oil and oil residue and contamination of soil, surface water and groundwater

Contamination of soil, surface waters, and groundwater Effect on human health.Risk depends on specific chemical (classify on individual basis)

Risk classification based on combination of probability of event occurring and severity of consequences Probability Severity of consequences Negligible (1) Minimal (2) Moderate (3) Severe (4) Extremely severe (5) Extremely likely (5) 3 3 4 4 5 Highly likely (4) 2 3 3 4 4 Likely (3) 2 2 3 3 4 Unlikely (2) 1 2 2 3 3 Extremely unlikely (1) 1 1 2 2 3

5 4 3 2 1

4

4

•

Biological sewage and domestic effluent treatment plant Metal precipitation in drains

1 1

Wastes for waste depot Wastes for recycling

5 4 3 2 1

1-4

3

•

1 1

1-4

2-3

Safety risks (fires, explosions, theft) Hazardous waste (more detailed list elsewhere)

1-5

2-3

Discharge to surface waters and groundwater Other risks • Atmospheric emissions

RISK CATEGORIES Probability of occurrence Extremely likely/probable Highly likely/probable Likely/probable Unlikely/improbable Extremely unlikely/improbable

Treatment of waste waters

Waste generated during production

Storage and transport of chemicals

5 4 3 2 1

Treatment plant meets performance standards Reduction of metal content by >95%. Water is directed to cover tailings and other waste areas where it inhibits dust generation

Operations in accordance with requirements of Waste Act and company specific waste plan. Hazardous waste regularly delivered to waste station for appropriate treatment and disposal Transported to waste depot Separated and sorted for distribution to recycling agencies for further use or processing

Specifically designed safety procedures according to attributes of chemicals Specifically designed safety procedures according to attributes of chemicals

APPENDIX 15. WORKING REPORTS AND OTHER PUBLICATIONS PREPARED DURING THE ”ENVIRONMENTAL TECHNIQUES FOR THE EXTRACTIVE INDUSTRIES” PROJECT

Hatakka, T. & Heikkinen, P. 2005. Pinta- ja pohjavesiseurannan järjestäminen kaivoksen sulkemisen jälkeen. Geologian tutkimuskeskus, julkaisematon raportti 30.9.2005. 14 s. Heikkinen, P. 2005. Hituran kaivoksen rikastushiekan mineraloginen ja kemiallinen koostumus. Geologian tutkimuskeskus, julkaisematon raportti 7.7.2005. 19 s. Heikkinen, P. & Jarva, J. 2005. Hituran kaivoksen ympäristön luontaiset taustapitoisuudet. Geologian tutkimuskeskus, julkaisematon raportti 13.9.2005. 26 s. Heikkinen, P., Kumpulainen, S., Kaartinen, T. & Wahlström, M. 2005. Kaivosten sivukivien ja rikastushiekkojen nettoneutraloimispotentiaalin määrittäminen – Menetelmävertailu – Esimerkkinä Hituran kaivos. Teoksessa: Salminen, R. (toim.): Seitsemännet geokemian päivät 24.25.22005. Tiivistelmät. Vuorimiesyhdistys, sarja B 83, 79-85. Heikkinen, P., Pullinen, A. & Hatakka, T. 2004. Hituran kaivoksen sivukivikasojen ja rikastushiekka-alueen ympärysojien pintavesikartoitus, virtaamamittaukset sekä ympärysojien ja kaivoksen vesien laatu toukokuussa 2004. Geologian tutkimuskeskus, julkaisematon raportti 29.10.2004. 29 s. Helminen, T. 2004. Tekes -hankkeen ’Kaivostoiminnan ympäristötekniikka’ työryhmä II:n kansainvälinen oikeusvertailu. Geologian tutkimuskeskus, julkaisematon tutkimusraportti 14.6.2004. 22 s. Juvankoski, M. & Tolla, P. 2004. Kaivospatojen ja -kasojen stabiliteettitarkastelut, VTT, Työraportti 6.11.2004. Kaartinen, T. & Wahlström, M. 2005. Hituran kaivoksen sivukivien ja rikastushiekan staattiset kokeet ja liukoisuuskokeet. Työraportti, VTT Prosessit 19.5.2005. 32 s. Kauppila, T. 2005. Kaivostoiminnan vesistökuormituksen vähenemisen vaikutus voimakkaasti muutettuun rehevöityneeseen järveen. Teoksessa: Salminen (toim.): Seitsemännet geokemian päivät, tiivistelmät. Vuorimiesyhdistyksen julkaisuja, Sarja B 83: 73-77. Kauppila, T. 2005. Mine water pollution effects on Lake Pidisjärvi, Finland. Securing the Future 2005, Skellefteå, abstracts: 519-528. Kauppila, T. 2006. Sediment-based study of the effects of decreasing mine water pollution on a heavily modified, nutrient enriched lake. Accepted to Journal of Paleolimnology (Vol 35:1) Kauppila, T. 2004. Outokumpu Mining Oy. Kalajoen ja Pidisjärven sedimenttitutkimukset. Geologian tutkimuskeskus, julkaisematon raportti 29.4.2004. 8 s. Kauppila, T. 2004. Sedimenttitutkimus Hituran kaivoksen vaikutuksista Pidisjärveen. Geologian tutkimuskeskus, julkaisematon raportti 27.10.2004. 17 s. Kumpulainen, S. 2004. Hituran kaivoksen sivukivikasojen pitkäaikaiskäyttäytymisen mallintaminen. Osa 1. Pitkäaikaiskäyttäytymisen arvioinnissa käytettävät menetelmät. Kirjallisuusselvitys. Geologian tutkimuskeskus, julkaisematon raportti 27.9.2004. 25 s.


Kumpulainen, S. 2005. Hituran kaivoksen sivukivikasojen pitkäaikaiskäyttäytymisen mallintaminen. Osa 2. Mallintaminen. Geologian tutkimuskeskus, julkaisematon raportti 3.7.2005. 31 s. Kumpulainen, S. 2005. Hituran kaivoksen avolouhoksen vedenlaadun mallintaminen. Osa 1. Avolouhoksen vedenlaatuun vaikuttavat tekijät ja arvioinnissa käytettävät menetelmät. Kirjallisuusselvitys. Geologian tutkimuskeskus, julkaisematon raportti 11.01.2005. Kumpulainen, S. 2005. Hituran kaivoksen avolouhoksen vedenlaadun mallintaminen. Osa 2. Vedenlaadun mallintaminen. Geologian tutkimuskeskus, julkaisematon raportti 7.5.2005. 24 s. Kumpulainen, S. & Heikkinen, P. 2004. Hituran kaivoksen sivukivikasojen kemiallisen ja mineralogisen koostumuksen vaihtelu. Geologian tutkimuskeskus, julkaisematon raportti 8.7.2004. 16 s. Leino, T., Suomela, P., Kosonen, M., Mroueh, U.-M., Nevalainen, J., & Mäkelä, E. 2005. Kaivoksen sulkemiseen liittyvä lainsäädäntö. Kaivostoiminnan ympäristötekniikka -projektin lakityöryhmän yhteenveto sulkemiseen liittyvästä lainsäädännöstä. Julkaisematon tutkimusraportti. 31.10.2005. Mroueh, U.-M., Heikkinen, P., Jarva, J., Voutilainen, P., Vahanne, P. & Pulkkinen, K. 2005a. Riskinarviointi kaivosten sulkemishankkeessa, 28.10.2005. VTT Prosessit. Projektiraportti PRO3/P3039/05. Mroueh, U.-M., Mäkelä, E. & Vestola, E 2005b. Paras käyttökelpoinen tekniikka kaivosten rikastushiekka- ja sivukivialueiden sulkemisessa. VTT, luottamuksellinen projektiraportti PRO3/P51/04. 14.10.2005. 25 s. Noras, P. 2005a. Sulkemisen omaehtoinen normitus. Geologian tutkimuskeskus, julkaisematon tutkimusraportti. Noras, P. 2005b. Sulkeminen ja kestävän kehityksen vaatimukset. Geologian tutkimuskeskus, julkaisematon tutkimusraportti. Saari, J. 2005. Yhteenveto Hituran perustilasta ja ympäristövaikutuksista. Vestola, E. 2005. Sulfaatinpelkistykseen perustuvat kolonnikokeet -jatkotutkimus. Raportti 23.6.2005. VTT Prosessit. 13 s. Vestola, E. 2005. Sulfaatinpelkistäjäbakteerien käyttö metallipitoisten vesien käsittelyssä. Ympäristö ja terveys 1/2005. Vestola, E. 2005. Hiturassa käytettyjen kemikaalien ympäristövaikutusten arviointi. Raportti 4.5.2005. VTT Prosessit. 15 s. Vestola, E. 2004. Sulfaatinpelkistäjäbakteerien hyödyntäminen happamien kaivosvesien käsittelyssä. TKK, Diplomityö. Vestola, E. 2004. Happamien vesien käsittely Suomessa. VTT prosessit. 3.11.2004. 11 s.

161

APPENDIX 16. EXAMPLE LIST OF CONTENTS FOR A TYPICAL MINE CLOSURE PLAN

1. Introduction 2. Background information 2.1 Site geology 2.1.1 Surficial materials 2.1.2 Bedrock geology 2.2 Characterization of mine environment 2.2.1 Climate 2.2.2 Landscape and topography 2.2.3 Surface waters 2.2.4 Groundwater 2.2.5 Flora and fauna 2.2.6 Land use and conservation 2.2.7 Cultural and socio-economic context 3. Current status of mine site and operations 3.1 Ownership and management issues 3.1.1 Mine ownership 3.1.2 Land ownership/leasing of mining concession 3.1.3 Legal requirements and permits for mining activities 3.1.4 Contracts and agreements 3.2 Activities and areas above ground 3.2.1 Area surrounding open pits or quarries 3.2.2 Open pit 3.2.3 Waste rock stockpiles 3.2.4 Overburden and surficial material stockpiles 3.2.5 Distribution of surficial materials and groundwater 3.2.6 Distribution of contaminated soil 3.2.7 Distribution of contaminated groundwater 3.3. Mine site 3.3.1 General background 3.3.2 Nature of ore and contained resources 3.3.3 Production planning 3.3.4 Underground equipment and infrastructure 3.3.5 Equipment and infrastructure above ground 3.3.6 Contracting arrangements 3.3.6.1 Areas and facilities in use 3.3.6.2 Equipment and machinery 3.3.7 Mine site maps 3.3.8 Area influenced by mining activity 3.3.9 Surface water and groundwater inflow to mine workings 3.3.10 Use of mine waters and discharge into surrounding areas 3.4 Tailings 3.4.1 Tailings impoundments 3.4.2 Tailings dams and embankments 3.5 Buildings and infrastructure 3.5.1 Crushing facilities 3.5.2 Concentrator mill (including maintenance workshops, office, concentrate storage bins and silos, chemical storage depots) 3.5.3 Storage depots –machinery maintenance workshop 3.5.4 Services buildings (recreational and social facilities), cafeteria, laboratories 3.5.5 Miscellaneous buildings (pre-mining legacy, ammunitions depots) 3.5.6 Other fittings and fixed infrastructure (electrical substations and transformers, power lines and cables, pipelines, thickening tanks, storage tanks) 3.5.7 Machinery and equipment 3.5.8 Supply depots 3.5.9 Roads

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4. Mine closure plan 4.1 General 4.1.1 Objectives of closure process 4.1.2 Stakeholders 4.1.3 Future land use options 4.1.4 Relinquishment and transfer of ownership rights, custodianship and responsibilities 4.1.5 Post-closure inspections and monitoring 4.2 Closure plan for areas above ground 4.2.1 Waste rock heaps 4.2.2 Concentrator plant site 4.2.3 Contaminated soils 4.2.4 Contaminated groundwater 4.3 Closure plan for mine workings 4.3.1 Open pit 4.3.2 Underground operations 4.3.3 Machinery and equipment 4.4 Closure plan for tailings area 4.4.1 Tailings impoundments 4.4.2 Tailings dams and embankments 4.4.3. Treatment and collection of seepage waters 4.5 Closure plan for buildings and infrastructure 4.5.1 Production facilities 4.5.2 Other buildings 4.5.3 Fittings and fixed infrastructure (electrical substations and transformers, power lines and cables, pipelines, thickening tanks, storage tanks) 4.5.4 Machinery and equipment 4.5.6 Supply depots 4.5.7 Roads 4.6 Closure management 4.6.1 Organization and personnel 4.6.2 Timetables and schedules 4.6.3 Expenses and budget estimations 4.6.4 List of items and actions 4.6.5 Image archives (final remedial works and site documentation) 4.6.6 Documentation of closure procedure 5. Post-closure inspections and monitoring 5.1 Surface water, groundwater and seepage water quality 5.2. Ecological state and physical and chemical quality of the down-stream watershed 5.3 Flooding of the mine workings and subsequent water quality 5.4 Physical and chemical stability of tailings and waste rock areas 5.5 Physical stability of mine workings 5.6. General inspection at the mine site 6. Contracts and permits 6.1 List of contracts and agreements 6.1.1 Land use 6.1.2 Material acquisitions 6.1.3 Energy supply 6.1.4 Water supply 6.1.5 Communications networks 6.1.6 IT systems 6.1.7 Contractors and service providers 6.1.8 Insurance and closure cost provisions 6.2 Permits 6.2.1 Mine register/dossier 6.2.2 Permits for discharge of mine waters 6.2.3 Waste management strategies 6.2.4 Environmental permits 6.2.5 Licenses for operating machinery and equipment 6.2.6 Sources of radioactivity 6.2.7 Electrical energy (110 kV) 6.2.8 Communications systems Mine Closure Handbook P. M. Heikkinen, P. Noras and R. Salminen (eds.)

APPENDIX 17. MINE CLOSURE PLANNING CHECKLIST

A. Issues to consider in relation to planning closure of underground mining operations: 1) Preparation of finalized map of mine workings and selection of representative drill cores for archiving • A current map is to be prepared, detailing mine workings up to the time of closure, and submitted to Safety Technology Authority of Finland (Tukes = Turvatekniikan keskus) • A representative range of cores and logging reports, relating to drilling during mining, is to be selected and submitted to the Geological Survey of Finland (GTK = Geologian Tutkimuskeskus), for storage at the national drill core archives 2) Measures taken to ensure that underground mine workings comply with requirements for general safety • Prevention of unauthorized access to mine workings (sealing entrances to declines and shafts, closure of mine access roads) • Delineation and fencing off areas susceptible to collapse or subsidence • Warning and prohibition signs affixed to fencing 3) Backfilling of underground workings subject to collapse or failure and stabilization with retaining barriers • Backfilling with waste rock or tailings, providing that there is no demonstrable risk to surface and groundwaters • Retention barriers constructed of quarried material or, if necessary, concrete 4) Removal of machinery and equipment and related infrastructure • Fixtures such as stairways and ladders installed during mining, particularly those relevant to mine safety, may only be removed at the discretion of the Ministry of Trade and Industry (KTM KTM = Kauppa- ja teollisuusministeriö) • All other machinery and underground installations are to be removed, including pipes and cables, and electrical equipment • Any fixed equipment or facilities remaining at the mine site should be drained of fuel and lubricants and any other materials that could potentially contaminate surficial or groundwaters • Servicing and maintenance workshops and accommodation, recreational and catering facilities, whether of concrete or wooden construction, are to remain • All waste and other materials that may potentially contaminate groundwater should be removed from the site • Materials destined for removal from the site should be sorted and stored for possible subsequent reuse or recycling 5) Cessation of dewatering of mine workings and assessment of whether water treatment is needed; implementation of treatment program if required 6) Land use strategies after mining has ceased • Assessment of collapse or subsidence risk in relation to future land-use planning, for example by classifying


the area separately in municipal building codes and excluding the relevant area from residential or industrial development or recreational zoning

B. Issues to consider in relation to closure of openpit mining operations 1) Preparation of finalized map of mine workings and selection of representative drill cores for archiving • A current map is to be prepared, detailing mine workings up to the time of closure, and submitted to Safety Technology Authority of Finland • A representative range of cores and logging reports, relating to drilling during mining, is to be selected and submitted to the Geological Survey of Finland, for storage at the national drill core archives 2) Measures taken to ensure that the area surrounding the open pit meets general safety requirements • Restriction of access to the open pit area (fencing enclosures, closure of access roads) • Isolating and fencing off areas at risk of subsidence or collapse • Landscaping and stabilization of pit edges and other areas prone to failure • Stabilization of rock walls potentially subject to collapse (mechanical strengthening and support, or slope reduction) • Affixing warning and prohibition signs to fencing 3) Potential infilling of open pits • Tailings and waste rock may be used as backfill, providing they do not represent a source of contamination for surficial or groundwaters 4) Removal of machinery, equipment and other fixtures from the open pit • Fixtures such as stairways and ladders installed during mining, particularly those relevant to mine safety, may only be removed at the discretion of the Ministry of Trade and Industry • All other machinery and equipment is to be removed from the site, including steel fittings and other materials • All waste and other materials that may potentially contaminate groundwater should be removed from the open pit • Materials destined for removal from the site should be sorted and stored for possible subsequent reuse or recycling; any further waste material remaining should be disposed of through appropriate treatment processes 5) Cessation of dewatering of the pit and assessment of whether water treatment is needed; implementation of treatment program if required 6) Landscaping in accordance with closure plan and future land use strategies • Planting of vegetation for stabilizing slopes and embankments • Ensuring that the area influenced by mining is registered appropriately for municipal land use planning (e.g in building code)

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C. Issues to consider in relation to closure of waste rock disposal sites: 1) Determination of waste rock characteristics (prior to commencement of mining) • Ascertain chemical and mineralogical composition, acid production potential, likely risk of dissolution of potentially hazardous compounds and long-term behaviour of waste materials • Determine physical, geotechnical and hydrological properties of waste rocks • Estimation of volume of waste rocks generated during mining 2) Determination of characteristics of surficial materials in substrate beneath planned waste rock storage areas and facilities (prior to commencement of mining) • Determine internal sedimentary and permeability structure of surface materials • Define groundwater and surface water flow • Design waste rock areas, preferably in locations where substrate has relatively low hydraulic conductivity 3) Determine options for utilization of waste rock (before and during mining operations • Maximize use of waste rock during mining and after mine closure to ensure minimization of material requiring ultimate placement as separate waste heaps • Potential applications include earthworks and road construction within the mining precinct, or elsewhere and backfilling within mined-out areas • Use of waste material is contingent upon results of geotechnical studies and compliance with environmental guidelines (refer to point 1 above) • Use of waste materials may require approval from relevant permitting authorities (refer to Section 3.1.1) • Stockpiling of material separately during mining for potential utilization, on the basis of differences in geotechnical or environmental properties 4) Ensure that the waste rock storage facilities remaining after mine closure meet the safety and stability requirements over the long-term, with respect to both physical and chemical behaviour • Mitigation of the risk of subsidence, slope failure and erosion by landscaping, designing structurally stable landforms, drainage systems and through stability investigations (refer to point J below) • Prevention of unauthorized access to dangerous areas and enclosure by fencing and clearly displayed warning signs • Assessment of need for covering the waste rock areas, with respect to long-term behaviour and risk of contamination by airborne dust, and if needed, determination of appropriate covering strategies 5) Evaluation of the risk of seepage water discharge from waste rock storage areas and appropriate containment and treatment strategies • Assessment of possible need for water treatment, based on environmental characterization of waste rocks, or (in the case of operating mines) on the quality, volume and discharge rates of seepage waters derived from waste storage facilities • Evaluation of the likely effects of other closure-related procedures on quality and quantity of seepage water discharge

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• Design of procedures and systems for water collection and drainage systems for passive and active methods of water treatment • Maintenance and monitoring plans for water treatment programs 6) Integration of waste rock storage facilities with surrounding environment and assessment of post-closure land use • Stabilization and landscaping of waste rock areas • Promotion of vegetation programs where necessary, by covering with topsoil and mulch, sowing mixed seed, planting of established seedlings, and furrowing and terracing to arrest erosion • Assessment and planning of post-closure land use options; clarification of ownership and custodial responsibilities and obligations • Determination of any potential restrictions on post-closure land use 7) Assessment of the need for ongoing monitoring of final waste storage sites and proposed performance guidelines and monitoring plans • Geotechnical monitoring of physical parameters to determine long-term stability of waste storage facilities • Facilitation and monitoring of vegetation programs • Monitoring seepage water quality and performance of treatment systems

D. Stockpiles of overburden in relation to mine closure planning: 1) Options for using stockpiled overburden during mining • Geotechnical characterization of different overburden materials to ascertain suitability for subsequent applications • Estimation of likely volume of overburden removed • Survey of potential applications: earthworks during mining or mine closure; planning of specific applications during mining start-up phase • Sorting and separate stockpiling of materials during mining, based on geotechnical or other material properties • Use of overburden materials may require approval under the Waste Act (1072/1993, refer to Section 3.1.1) 2) Ensure that overburden stockpiles comply with general safety requirements • Landscaping to ensure physical stability and aesthetic objectives of landscape restoration • Implement vegetation programs as needed

E. Closure planning in relation to mine tailings impoundments: 1) Physical and chemical characterization of tailings (before commencement of mining) • Chemical and mineralogical composition, acid production potential, likely risk of dissolution of potentially hazardous compounds and long-term behaviour of tailings materials • Assessment of seepage water quality during initial processing and enrichment tests • Characterization of geotechnical and hydrological properties


2) Characterization of material properties of substrate to proposed tailings impoundment (prior to commencement of mining) • Internal sedimentary and permeability structure of surficial materials • Surficial and groundwater conditions • Design location of tailings impoundment, preferably on substrate with relatively low hydraulic conductivity 3) Determine options for use of tailings (before and during mining operations) • Attempt to minimize final amount of tailings by maximizing opportunities for use, during both active mining and closure • Potential applications include earthworks at the mine site or elsewhere in the vicinity, or backfill within the mine workings. In some cases, tailings materials may be suitable for soil improvement or for agricultural purposes (e.g as fertilizer) • Use of tailings is subject to determination of relevant geotechnical and environmental properties (refer to point 1 above) • Appropriate statutory permits may be required before tailings can be utilized (refer to Section 3.1.1) 4) Ensure that remaining tailings impoundments comply with general safety requirements and are demonstrably chemically and physically stable with respect to longterm environmental risk • Ensure stability of tailings impoundment dams and embankments; stability investigations, landscaping, drainage systems, vegetation programs (refer to point J) • Draining of settling ponds and dismantling of an unnecessary earthworks, including assessment of potential use of material elsewhere; determine final storage options for sludge accumulated on the bottom of the settling ponds • Prevention of unauthorized access to potentially dangerous areas and enclosure by fencing with clearly marked warning and prohibition signs • Assessment of need for tailings covers, with respect to long-term behaviour and risk of contamination by airborne dust, and if needed, determination of appropriate covering strategies • Determine appropriate timing for implementing covering program: usually can be commenced during mining • Determine whether tailings discharge into the surrounding groundwater, map discharge sites and contain release of seepage waters; evaluate possible need for groundwater treatment and choose appropriate remedial methods 5) Determine need for treatment of waters discharging from final tailings impoundment after mine closure, including appropriate operational plan • Evaluate need for water treatment program, based on environmental characterization of tailings, or (in the case of operating mines) on the quality, volume and discharge rates of seepage waters derived from tailings impoundments • Estimation of potential effects on amount and quality of seepage water discharge resulting from any other closure-related procedures • Design appropriate procedures for water collection and containment, drainage systems and passive or active forms of water treatment


• Prepare maintenance strategy and monitoring plan for selected treatment program 6) Ensure integration of tailings impoundments with surrounding environment and assessment of post-closure land use • Stabilization and landscaping of tailings impoundments and embankments • Promotion of vegetation programs where necessary, by covering with topsoil and mulch, sowing mixed seed, planting of established seedlings • Ensure that the tailings area is assigned separate status in municipal land use zonation and building codes • Assessment and planning of post-closure land use options; clarification of ownership and custodial responsibilities and obligations • Determination of any potential restrictions on post-closure land use 7) Assessment of the need for ongoing monitoring of tailings areas and defining monitoring procedures • Geotechnical monitoring • Monitoring amount and quality of seepage water production and discharge • Monitoring performance of water treatment systems and other related closure procedures

F. Issues to consider with respect to buildings and infrastructure during decommissioning and closure: 1) Ensure that area is restored to a state complying with general safety requirements • Dismantling of unsafe or unnecessary buildings and structures • Removal of tanks, drums and other containers for storage of chemicals • General cleaning and landscaping of mine site • Environmental audit of potential risk or contamination relating to remaining infrastructure and propose risk abatement or remedial measures 2) Evaluation of possible options for ongoing use of remaining mine infrastructure • Infrastructure specifically constructed for the purposes of maintenance of mine safety, and structures designed solely for mining activities, such as concrete headframes at the concession, can only be dismantle or removed if permission has been granted by the Ministry of Trade and Industry (KTM = Kauppa ja Teollisuusministeriö) 3) Inventory of infrastructure and assessment of potential options for reuse • Evaluation of potential need for using roads and buildings and other infrastructure and potential opportunities, for example for industry or other commercial activities • Evaluation of potential cultural significance of mining infrastructure, designation of sites for protection and conservation • Clarification of ownership issues and liabilities in relation to infrastructure remaining at the mine site 4) Dismantling buildings and infrastructure • Assessment of potential reuse options for dismantled structures (recycling, energy value) • Sorting of materials • Safety precautions if hazardous materials are present (asbestos) • Disposal of materials in appropriate manner

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G. Decommissioning and removal of plant and machinery in relation to mine closure: 1) Removal of mining plant, machinery and equipment from the mine site • Plant or equipment whose purpose is specifically related to maintenance of mine safety can only be removed after approval has been granted by the Ministry of Trade and Industry. All other machinery and equipment is to be removed from the site • Assessment of potential for deploying or reusing equipment and plant elsewhere, including resale value, recycling of components or possible use in energy production • Evaluate options for selling concentrating plant • Appropriate disposal of equipment that is unsuitable for reuse or recycling • Environmental risk assessment in relation to mining plant and equipment

H. Issues to consider in relation to mine site vegetation programs: 1) Future land use activities and aesthetic considerations 2) Requirements for effective and sustainable vegetation cover: • Assessment of nutrient state/requirement for fertilizer • Determine humus content, pH and potential contaminants that might inhibit growth • Determine moisture content • Determine whether substrate has sufficient depth for establishment of large plants and establish whether addition of topsoil or mulch is needed • Determine susceptibility to erosion and need for terracing or furrowing 3) Characterize endemic plant taxa and assess their suitability for planting and revegetation programs 4) Identify other plant taxa for planting, and assess their suitability • Determine climate tolerance, growth rate • Optimum substrate requirements • Effectiveness as ground cover and stabilization capacity of root systems; assessment of potential damage of the root penetration on the performance of cover structures 5) Requirements for maintaining and promoting growth, plan for on-going monitoring of revegetation program

I. Checklist of monitoring procedures for surficial and ground waters • Perform thorough study of surficial and groundwater conditions at the site (refer to Section 4.1.1) • Document all drainage methods and systems in relation to mine closure, including tailings and waste rock storage facilities; conduct research on water chemistry and associated processes • Identify locations of domestic wells in proximity to the mine • Determine appropriate density and locations for sampling network required for post-closure monitoring of surficial and groundwater quality

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• Document all known observation stations relating to groundwater, including observation well characteristics (location, general condition, depth, diameter and composition of tube materials and lining), which should normally be found in reports relating to installation of the tubes. Assess suitability of observation wells for post-closure groundwater monitoring • Evaluate the need for installing a more extensive array of observation wells at the site and determine the most appropriate tube materials and size. Define locations, depths and appropriate well screen length, so as to ensure representative sampling of the groundwater column, taking into account natural variations in depth to the water table • Based on previously available water chemistry data, define the most significant variables for measuring during post-closure monitoring, as well as analytical requirements • Prepare a practical implementation plan for water quality monitoring, including assignment of responsibility for sampling, equipment required for sampling, specification of sampling procedures appropriate for local site conditions, analytical techniques and reporting procedures. In addition, frequency of routine sampling, as well as random inspections, should be defined. • Assessment of need for independent verification of accuracy of water quality measurements • Define procedure for reporting results of monitoring program • Estimate likely annual budget for monitoring program • Provide complete monitoring program plan to relevant authorities

J. Checklist for monitoring stability of embankments and waste rock and tailings facilities Checklist relating to stability investigations: 1) Compile and collate available background data • Compile information relating to previous geotechnical ground surveying • Compile information relating to dimensions and geometry of earthen structures • Compile data on pore water levels in mine structures, general depth to phreatic surface and water table fluctuations • Compile database of strength parameters of relevant materials • Assess whether above data are current and adequate • Determine what kind of additional investigations, including field studies and laboratory experiments, might be necessary to supplement existing data, and • Assess the potential effect of mine closure procedures on the stability of structures 2) Performing site stability investigations • Determine potential failure surfaces with lowest safety factor along specified transects through dams and embankments • Perform risk and sensitivity analyses 3) Closure procedures • Planning and implementation of a monitoring program for activities related to mine closure


Post-remediation activities and monitoring Geotechnical inspections are carried out after completion of the site rehabilitation program, to check structural stability and that structures and systems meet performance criteria, and to make sure that any potential problems or shortcomings can be identified and addressed at an early stage. A regular site inspection program should include: • Visual assessment of the overall area and structures • Inspection of water levels, including pore waters • Checking the amount of seepage water discharge related to dams and embankments • Assessment of the need for precise leveling measurements to check for evidence of displacement or creep Specific features to examine during visual inspection of the mine site and structures are as follows: 1) General site inspection, paying attention to • Condition of fencing and enclosures • Condition and performance of monitoring equipment 2) Inspection of open pits and waste rock stockpiles: • Possible displacement or deformation and erosion of slope and embankment surfaces • Effectiveness of surface drainage and drying schemes 3) Structural integrity of dams and embankments and related structures are assessed by observing in particular: • Possible deformation and displacement of the outer slope of dams and embankments, particularly at lower levels • Evidence of erosion of embankment material by surface water runoff or seepage water infiltration • Evidence of fissuring or fracturing within embankment material or terraces and berms. • Effectiveness of drying and drainage schemes and systems • Establishment of vegetation on dams and embankments (colonization and growth, extent of groundcover, presence of large trees) • Evidence of deformation, fissuring or subsidence in tailings and waste rock cover materials • Effectiveness of drying strategies in cover materials • Establishment and condition of vegetation on covering material All dams and embankments should be inspected immediately after intense rainfall events.


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APPENDIX 18. AUTHOR CONTACT INFORMATION The most significant responsibilities in preparing the handbook are indicated in parenthesis after each author’s name. Geological Survey of Finland P.O. BOX 1237 FI-70211 Kuopio, Finland E-mail: firstname.surname@gtk.fi Geological Survey of Finland P.O. BOX 96 FI-02151 Espoo, Finland E-mail: firstname.surname@gtk.fi

Environmental geologist Päivi M. Heikkinen (ed., 1.1, 1.2.1, 1.2.2, 1.2.4., 2.1, 2.4, 5.2, 5.4.1, 5.5, 5.6, 6.1, 6.2.1, 7., 9., Appendixes 10., 14., 15., 17. and 18.)

Senior research scientist Tommi Kauppila (5.2)

Debuty director - International services Pentti Noras (ed., 1.2.3, 1.2.4, 2.2.3, 2.3, 8., Appendixes 2. and 3.)

Research professor Reijo Salminen (ed.)

Geologist Tarja Hatakka (7.1, Appendix 17.) Environmental geologist Jaana Jarva (5.8, 6.1.8, Appendix 11.)

Senior research scientist Jussi Leveinen (5.6, Appendix 10.) Division manager Petri Lintinen (5.1)

Ministry of Employment and the Economy (Ministry for Trade and Industry)

Chief Inspector of Mines Pekka Suomela (3.1, 3.2, 3.3, 3.6, 6.3.2, 6.4)

E-mail: pekka.suomela@ktm.fi

VTT P.O. Box 1000 FI-02044 VTT, Finland E-mail: firstname.surname@vtt.fi

Research scientist Tommi Kaartinen (5.4.2, Appendix 9.)

Senior research scientist Pasi Vahanne (4.1, tables in 6.1, Appendix 1)

Professor Veikko Komppa

Research scientist Elina Vestola (6.2.1, Appendix 12.)

Customer manager Ulla-Maija Mroueh (2.2.1, 2.2.2, 3.4, 4.2, 6.2.2, 6.2.3, Appendixes 6., 13.,14. and 17.)

Senior research scientist Margareta Wahlström (5.4.2, Appendix 9.)

Team leader Esa Mäkelä (3.4)

Research scientist Markku Juvankoski (5.7, 7.2, Appendix 17.)

Outokumpu Oyj P.O. BOX 140 FI-02201 Espoo, Finland

Manager - Environmental legal issues Tiina Leino (3.1, 3.2, 3.3, 3.5, 6.3.2, Appendixes 4. ja 7.)

E-mail: [email protected]

Dragon Mining Ltd / Polar Mining Oy Kummunkuja 38 FI-38200 Vammala, Finland

Manager - Operations Heimo Pöyry (1.2.2, 6.1, 6.3.1, 8., Appendix 16.)

E-mail: heimo.poyry@dragonmining.fi

Soil and Water Ltd. P.O. BOX 50 FI-01620 Vantaa, Finland

Vice president Mirja Kosonen (3.1, 3.6, 3.7, 6.4, Appendix 5.)

E-mail: mirja.kosonen@poyry.fi

Lassila&Tikanoja Oy (Salvor Oy / Tieliikelaitos) Hatanpään valtatie 24 FI-33100 Tampere, Finland

Export manager Jukka Nevalainen (3.2, 3.5, Appendix 8.)

E-mail: jukka.nevalainen@lassila-tikanoja.fi

GeoPex Oy (Salvor Oy / Tieliikelaitos) Harjuntie 95 FI-45200 Kouvola, Finland

Managing director Pekka Vallius (5.9)

E-mail: pekka.vallius@geopex.fi

Destia Oy (Tieliikelaitos) P.O. BOX 157 FI-00521 Helsinki, Finland

Chief Consultant (Geotechnical Engineering) Panu Tolla (5.7, 7.2)

E-mail: panu.tolla@destia.fi

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DOCUMENTATION PAGE

Publishers

Geological Survey of Finland (GTK), Technical Research Center of Finland (VTT), Outokumpu Oyj, Finnish Road Enterprise, and Soil and Water Ltd.

Date May 2008

Authors

P. M. Heikkinen (ed., GTK), P. Noras (ed., GTK) and R. Salminen (ed., GTK) U.-M. Mroueh, P. Vahanne, M. Wahlström, T. Kaartinen, M. Juvankoski, E. Vestola and E. Mäkelä (VTT), T. Leino (Outokumpu Oyj), M. Kosonen (Soil and Water Ltd.), T. Hatakka, J. Jarva, T. Kauppila, J. Leveinen, P. Lintinen and P. Suomela (GTK), H. Pöyry (Outokumpu Mining Oy), P. Vallius and J. Nevalainen (Salvor Oy), P. Tolla (Finnish Road Enterprise) and V. Komppa (VTT)

Title

Mine Closure Handbook

Abstract The Mine Closure Handbook has been compiled within the Tekes-financed project “Environmental techniques for the extractive industries” and it has been directed to mining companies, authorities and consultants. The planning and implementation of mine closure are constrained by legislative requirements that define criteria and objectives for closure, as well as dictate responsibilities and sanctions. In addition to legislation, principles of sustainability, best practice and environmental management systems provide guidelines for closure. The wide variety of raw materials mined and the differences in operations are reflected in mine closure planning and implementation. The selection of methods employed is dependent on e.g the nature of the deposit and the production process, the type and properties of the by-products and the environmental conditions at the site. The selection of methods must be based on site-specific considerations. The introductory section of the Handbook describes the special features of mining projects, e.g the life-cycle and environmental impacts of mines. The structure and importance of mining industry in Finland are also reviewed. The next section discusses the general principles and aims of mine closure, while the subsequent section on legislation reviews current legislatory requirements for mine closure and presents case law and permit decisions. The following sections describe procedures of environmental impact assessment and risk assessment related to mine closure and present examples of studies that can be used to support planning. After the planning section, the Handbook focuses on the implementation of mine closure and presents technical solutions and risk control measures of relevance to closure. The final sections deal with aspects of after closure monitoring and cost accounting. The appendices of the Handbook provide in-depth views of the most important topics raised in the main text.

Keywords

Mines, mine closure, planning, legislation, environmental geology, environmental effects, risk assessment, remediation, manuals, Finland

Project name

Environmental techniques for the extractive industries

Financier/commissioner

Tekes and participating organizations

Project organization

See publishers ISSN

ISBN 978-952-217-042-2

No. of page 169

Language English

Restrictions Public

Price Freely available

Distributor

See publishers

Financier of publication

See publishers

Printing place and year

Vammalan Kirjapaino Oy, Vammala 2008


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